Crocodiles miscellaneous and others

Crocodiles miscellaneous and other issues :

1-How do you sex a crocodilian?

courtesy to : crocodilian.com/crocfaq/faq-8.html

Male and female crocodilians can be hard to tell apart visually. Usually, the best indication is size - males grow larger than females in all crocodilian species, and so a very large individual is more likely to be a male. In some species, females may have narrower snouts, and a more slender body, but such traits are highly unreliable indicators of sex. In larger crocodilians, the shape of the vent can provide a guide to the animal's sex. Females tend to have smaller, narrower and flatter vents (Fig.1) whereas

males have larger, wider, and more convex vents (Fig.2). This difference is due to the increased elasticity of the vent in males necessary to allow eversion of the penis during copulation. However, the differences visible in these pictures are rarely so clear-cut. There's only one realistic way to be 100% certain - looking inside the vent.

Figure 1. Vent of an adult female crocodile.

Figure 2. Vent of an adult male crocodile. Compared with the female vent, it is larger and more convex. Be warned, however, that such differences are rarely so obvious - there is no substitute for internal examination.

To be certain of a crocodilian's sex, you need to either feel or visually identify the penis (male) or clitoris (female). In big animals, this is very easy - look at the photos to the left and you will see there is no doubt which is male and which is female. In smaller animals, however, it requires a lot more experience and skill to do it properly and not make a mistake. It's a good idea to find someone with suitable experience (e.g. a vet, or zoo personnel) to show you how to perform it safely and accurately.

The actual procedure in large animals involves inserting a clean finger into the vent and feeling for the copulatory organ. Don't be afraid to push your finger in some way - you will not harm the animal. The male has a single, very obvious penis (Fig. 3) with a fleshy head and a cartilaginous shaft. It originates from the wall of the cloaca directly in front of the vent on the belly side, and curls backwards so the shaft and head lies directly beneath the vent opening. So, if you feel a slightly soft, cylindrical tube with a fleshy end, you've got a male. In fact, turning a male over will often cause it to evert its penis for you (and void the contents of its cloaca too), leaving you in no doubt. Females have a clitoris in the same location which is quite similar in shape to the male's penis, but it is much smaller (Fig. 4) and not cartilaginous. Unless you're experienced, it can be possible to mistake the clitoris for a small penis in younger animals, although the distinction is usually clear in larger males (Fig. 5). Again, females will often try and void the contents of their cloaca when you turn them over, but in this case you won't see the penis emerge, though you may just see the tip of the clitoris in the corner of the vent.

Although this procedure does not harm the animal if performed correctly, crocodilians generally object to such demeaning behaviour. Therefore, the animal should be restrained by a second person throughout the procedure.

Figure 4. The tip of an adult female's clitoris, similar in appearance to the tip of the male's penis but much smaller. It is usually not possible to evert the clitoris any more than this from the cloaca.

Figure 3. The tip and shaft of a sub-adult male's penis, partially everted from the cloaca.

Figure 5. Fully everted penis of large adult male crocodile. The groove running down the centre conveys semen to the tip, and the two masses at the base are the muscles used to evert the penis during copulation. The male's testes are inside the body cavity.

And just in case you're confused, males have a single penis, not a pair of hemipenes like most other reptiles. It can be confusing because the tip of the male's penis is split into two halves, so if you're just peeking inside the vent, you might think you were looking at a pair of hemipenes. Once the male extends himself, however, you'll be in no doubt whatsoever.

Sexing hatchlings and small juveniles is a different matter. There are two commonly used methods: some prefer one, some prefer the other.

1. Spreading the vent: For the first method, you need a pair of blunt forceps, haemostat, or similar device. You use these - with extreme care - to spread the vent apart so you can see down into the cloaca (see right). Having a torch or a good light source behind you is often a good idea.

Get someone else to hold the animal, turn it upside down, and place it on a solid surface. You don't want the animal struggling and moving around whilst you've got those forceps in there, so holding it down must be done properly. With the fingers of one hand, pull the lips of the vent apart, and with the other hand slowly insert the closed forceps. It's a good idea to put a few drops of oil or water on the forcep tips so they slide in more easily. Once you've gone down no more than 5 to 10 mm (with a hatchling), slowly and gently open the forceps up, which should spread the vent. Assuming you've got light available, you should be able to see down inside the vent. It'll be pink and dark in there, but you're looking for what's called the "cliteropenis" - it's called that because the male's penis and the female's clitoris are relatively similar in appearance (undifferentiated) with hatchlings. This structure is attached to the ventral, anterior surface (in English, that is the underside of the upper surface in front of you, assuming the animal is upside down and the head is facing away from you). It's small, and shaped like a small V.

This is the hard part, and it's something you'll only get good at with experience. In the male, this structure is larger, longer, more tubular and has a more rounded head, compared with the female's structure (which some describe has having a slightly more triangular base). The diagram (left) shows a rough approximation of what the cliteropenis looks like in C. johnstoni (after Webb, Manolis and Sack 1984). Because the male's penis is slightly longer, it's slightly

As the animal gets bigger, sexing the animal gets a lot easier. Basically, the male's penis grows much faster than the female's clitoris, so the difference in size and shape between the two becomes increasingly obvious. You have to be careful, though, because often there is a lot of overlap between the size of the penis and the size of the clitoris - some sub-adult females can occasionally have a slightly larger clitoris than the penis of rather unlucky males of the same size, but of course in bigger animals this overlap disappears.

2. Popping: This second method can only be used in young hatchlings - it doesn't work with older and larger animals. This method is referred to as "popping", because you use pressure on the tail to literally pop out the male's penis (if it's there). As before, this needs to be done very carefully, without applying an excessive amount of pressure, otherwise you'll injure the animal. Although you can do this by yourself, it's a lot easier with a second person to help you.

Figure 6. Holding a crocodilian upside down like this usually causes muscle relaxation. The head is restrained gently with one hand, leaving the other free to perform the procedure.

The images on the left illustrate the procedure. Please remember to be gentle with the animal - use common sense and do not apply too much pressure either bending the tail or squeezing the sides of the vent. Hatchlings are fragile and should be treated with care.

It's easier if you hold the animal away from a surface. Hold the animal upside down in one hand (Fig.6) which should cause it to relax. The other hand is now free to bend the tail and spread the vent. You can either bend the tail towards the animal's belly (Fig. 7) so that you compress the vent, or you can bend the tail away from the belly so you stretch the vent (Fig. 9). The former method is preferable with caimans. Again, use common sense here - don't bend the tail too far or you'll break the poor little guy's back. Next, using your thumb and index finger, pull the vent apart from either side, and then apply pressure to either side of the vent (Fig. 7). This takes a little practice, and you might need to shift pressure forwards and backwards until you hit the right spot (with a second person holding the animal you can use both hands which can be a lot easier). What happens is that the vent should start to spread outwards, and then the tip of male's penis should literally pop into view (Fig. 8) . If you don't see an obvious cliteropenis like that in Fig. 8 then it's much more likely that you've got a female. Don't apply too much pressure - if there is no obvious penis then stop as you almost certainly have a female. The popping method is easier and quicker than probing the vent, and works very well in some species especially caimans, but probing the vent is more reliable when done by an experienced person.

Before you get the urge to rush off and sex your crocs, just bear in mind that it gets a lot easier as the animal gets larger. Unless you have a very good reason to sex a hatchling or juvenile, it's probably better to wait so you can be sure. Conversely, the larger the croc, the greater its ability to object by sinking its teeth into your arm!

- Joanen, T. and McNease, L. (1978). The cloacal sexing method for immature alligators. Proc. Ann. Conf. S.E. Assoc. Fish & Wildl. Agencies 32: 179-181

- Webb, G.J.W., Manolis, S.C. and Sack, G.C. (1984). Cloacal sexing of hatchling crocodiles. Australian Wildlife Research 11, p.201-202

Figure 7. A dwarf caiman being popped by bending the tail gently upwards and applying pressure to either side of the vent. You can see the cliteropenis emerging from the vent. You can see that the tail does not need bending very far for the method to work.

Figure 8. A close-up of the vent being popped by gently bending the tail upwards and applying pressure on either side of the vent. In this case, the animal is clearly a male - the penis projects some distance above the vent.

Figure 9. Although bending the tail upwards is the better method, the animal can also be popped by bending the tail downwards. This stretches the vent and the penis emerges, although it is not as clearly visible as in Fig. 9.8.

Figure 10. Larger crocodilians, like this 3.5 ft American alligator, can also be popped. However, once the vent is large enough to insert your finger into, popping becomes redundant.

The flared tip of a spectacled caiman's penis.

2- Can I keep my caiman with other animals?

It's generally not a good idea to keep your caiman with other animals, given that the caiman may well regard them as food. In some cases, other animals may even regard your caiman as food! It is not uncommon to hear reports of turtles and even fish nibbling away at a caiman's tail or toes, especially when they don't have sufficient food themselves. However, some owners have reported that caimans get along well with turtles, as long as the turtle is too big to fit inside the caiman's jaws. An adult caiman is quite capable of crushing a smaller turtle's shell. One owner reports that a caiman bit the head of a turtle while they tussled over a piece of food, and also that snapping turtles make poor companions with smaller caimans, whom they regard as food. Turtles are also quite capable of passing parasites (e.g. leeches) onto crocodilians.

Caimans are often kept together with other crocodilians, but their compatibility depends upon the species and size. Some species are highly intolerant of others. More importantly, if there is a large size difference between the animals, there is a very good chance that the larger animal will kill and eat the smaller one - even if they are the same species (cannibalism is common amongst crocodilians). On the other hand, I've seen very large caiman exhibits populated with species of varanid lizards. It depends on the amount of space available, and whether there is suitable habitat partitioning between the different occupants. However, for most home set-ups, it is recommended to keep the caiman in a separate enclosure. Fights between larger, aggressive males can often maim and kill one or both individuals, so consider this advice carefully.

3-Should I monitor the caiman's progress?

It is definitely a good idea to monitor your caiman's growth - measure its total length and snout-vent length on a regular basis, and try to weigh it. This information satisfies more than just an interest in your animal's growth rate, but can provide vital clues on your caiman's health - a loss of weight, for example, is one of the earliest indicators of a more serious problem. Your vet will also find this information very useful if the day comes that your caiman requires treatment. Regular vet visits are always a good idea, and data from the occasional blood panel can provide valuable information to assist future diagnosis and treatment.

4-Where can I find a good home for my caiman?

You need a very good reason for asking this question. It is mentioned here for one simple reason - to prevent people from dumping unwanted caimans in the nearest stream or pool. Releasing caimans into the wild might seem to be an eco-friendly thing to do, but it will result in one of two outcomes. Either your spurned pet will die, or it will become a serious nuisance. Released pet caimans in Florida are disrupting native wildlife, and crocodilians released into areas where there are normally none can still bite unsuspecting people and eat family pets. If you absolutely have to get rid of your animal, don't release it into the wild.

You'll find that local zoos, aquaria or crocodile farms will almost certainly not be interested in your animal - nor the dozens of similar animals they are asked to take each month. Perhaps the best bet is to contact other private crocodilian enthusiasts or herpetological societies who would much rather give it a good home than see it released to die. Few other people would be experienced or qualified enough to take an aggressive crocodilian off you.

If you still can't find anyone to take the animal, perhaps you should reconsider. The only alternative is euthanasia - is your caiman really so disposable?

5- Where can I find more information on the Internet and in books?

There isn't much information on caiman care on the Internet, but recently some excellent work is now available to read. There is also a good selection of quality information on crocodilians, whether you're researching biology or just searching for decent photographs.

For information specific to caiman care, visit:

http://crocodilian.com/paleosuchus - Colin Stevenson's highly commendable website dedicated to the Paleosuchus genus
http://crocodilian.com/crocfaq - this document's home on the Internet

For general crocodilian info, visit:

http://crocodilian.com - species information, biology database, sound library and links by Dr Adam Britton [maintainer of this FAQ]
http://www.erols.com/reptiles - John White's reptile page, containing a gallery of crocodilian pictures
Both crocodilian.com and the Crocodile Specialist Group site contain dedicated link pages to a wide range of different crocodile sites.

For general information on crocodilians:

Ross, C.A. (1989). Crocodiles and Alligators. Weldon Owen Pty Ltd, New South Wales. 240 pages
Webb, G.J.W. & Manolis, C. (1989). Crocodiles of Australia. Reed Books Pty Ltd, New South Wales. 160 pages For veterinary care:
Fowler, M. (1986). Zoo & Wild Animal Medicine. 2nd edition. W.B. Saunders Co., PA. [contains a modest amount of information on crocodilians]
Frye, F.L. (1981). Biomedical and Surgical Aspects of Captive Reptile Husbandry. Veterinary Medicine Publishing Company, Edwardsville, Kansas. pp. 458 [contains much of the groundwork for modern reptile medicine]
Mader, D.R. (1996). Reptile Medicine and Surgery. W.B. Saunders Co., PA. 512 pages [general information, with little specific to crocs] For wildlife management:
Webb, G.J.W., Manolis, S.C. & Whitehead, P.J. (1987). Wildlife Management: Crocodiles and Alligators. [includes information on captive farming techniques]

Many books you can find in the Internet based libraries and bookshops like Amazon.com ( Click Here ) ..

But first look for the best prices at Book Finder.com

6- How to Purchase a crocodile ?

courtesy to : crocodilian.com/crocfaq/faq-8.html

Where can I buy a caiman?

Caimans and a few other crocodilian species are available from several sources, dependent upon local laws. In areas where selling crocodilians is legal, you'll find them at specialist pet stores. They are also available through various distributors who trade over the Internet and through hobbyist reptile magazines. On the Internet, one of the best places to start is http://www.kingsnake.com where a number of dealers advertise. Good magazines to buy in the US would be Reptiles and The Vivarium. In Europe, look to Reptilia. You may also be able to buy privately from experienced keepers who may advertise hatchlings or adults for sale in any of these publications. A list of possible sources which sell or advertise crocodilians for sale can be found in Appendix III.

Also, consider contacting your local herpetological society. A high percentage of caimans and other crocodilians are dumped by their owners who either get bored of them or who are bitten once too often. Herpetological societies are often the benefactors of far too many caimans, and would be happy to see at least one of them go to a good home. However, they are usually very careful to ensure that any potential owners are up to the task, and will refuse to let an animal go to anyone who doesn't have the right permits, the right experience, or the right setup.

What do I need to consider when buying a caiman?

Before you purchase any animal, never mind a caiman, you need to make sure you've thoroughly researched its requirements, and that you have everything you need for it already. Make sure you have the right permits if they are required, and that you've built the tank or enclosure in which you plan to keep the animal. You won't believe how many people buy the animal first (especially if it's from a pet store) and then try and figure out how to house it!

If you're buying mail order, then obviously you can't inspect the animal before you buy it. It goes without saying, however, that you should receive a healthy and uninjured specimen. If you're able to see the animal before you buy it, check it thoroughly - pick it up and examine it, although do so without getting bitten. The animal should be alert and active, often trying to bite and vocalise. Lethargic animals should be treated with suspicion (they could be ill, or simply too cold) although some individuals are naturally calmer than others while still being alert. Check for injuries. Small cuts, scratches and bites are common in crocodilians kept together, but they must be minor. Ensure that the skin is clean, smooth on the belly and free from fungus. The eyes and nictitating membrane should be clear and open fully. The nostrils should be clear of any discharge, and the mouth clean. Check for inflammation around the back of the throat that could be indicative of respiratory problems or secondary infections. The vent should be clean. Check also for mites and other parasites that can get into the folds of skin around the eyes, and within the earflaps. Parasites are not normally a major concern with crocodilians, but their presence occasionally may be indicative of a more serious problem. Check the tail base, which should be relatively plump and firm - the base of the tail and the neck are two areas where fat is stored, and animals which aren't eating will lose condition here first. Larger animals that become emaciated also show a loss of condition around the shoulders - the enlarged, nuchal plates on the neck become very conspicuous. If you're dealing with a hatchling, check the belly for a yolk scar. This should only be visible in animals that are under a few weeks old, although in some species (e.g. Alligator mississippiensis) the scar persists throughout the animal's life. There should be no excess tissue attached to the yolk scar either - the belly should be almost completely smooth. Newly hatched animals often show incomplete closure of the belly skin over the yolk sac, but this will disappear in a day or two after hatching. An infection of the yolk sac, however, will lead to an early death.

How much can I expect to pay?

The cost of an individual animal varies depending on the species, size of the animal, and the area in which you live. Animals from private breeders are often cheaper than those from pet stores (e.g. double the costs listed below if you buy from a pet store in Germany). The prices listed below are for hatchlings and juveniles, which are the size classes normally offered for sale. They are meant as a rough guide only to give you some idea, so please don't treat this as an official source. The different currencies are provided only to show the range of prices in that particular country.

SpeciesUS dollars 9 Prices as per 1996

Caiman crocodilus : $50

Paleosuchus palpebrosus : $125

Paleosuchus trigonatus : $200

Osteolaemus tetraspis

Alligator mississippiensis

Alligator sinensis

Crocodylus johnstoni : $300

Genetic colour variations fetch ridiculous prices, and are generally more trouble than they're worth to keep unless they're for public display, you have someone to impress or you plan on breeding them in the long-term.

Remember that the cost of purchasing the animal is but a tiny fraction of the amount you'll have to invest to set it up and maintain it correctly.

Is there anything else I need to buy?

When you purchase your crocodilian, you should have the rest of your set-up in place. This will include the enclosure itself and other items such as water filters, water heaters, air heaters, lighting, thermometers, substrate, furnishings, and food. Other items, depending on the size of the crocodile, might include gloves and some method of restraint such as a catch pole. Once you've read this FAQ thoroughly, you should have a good idea of what you'll need for your animal.

How do I transport my caiman?

If you need to transport a crocodilian any distance, whether by car or by air, you must ensure that it's housed in a secure, comfortable and safe container for the duration of the journey. The type of container will depend upon the size of animal, the transportation method, and any shipping requirements which need to be satisfied. All shipping companies, such as Delta-Dash, U.S. Mail, UPS or Air Borne Express (for zoo animals only) have specific policies regarding the shipment of crocodilians, so talk to them first before you prepare the animal for travel. For example, United States Postal Service (U.S. Mail) will ship crocodilians up to 20 inches (domestic mail manual, code section CO22.3.2) and Delta Airlines (Delta Dash) will ship crocodilians where the animal and its container do not exceed 50 lbs. The following information provides a useful guide to ensure that your animals survive the journey in one piece.

Hatchlings can be transported in a non-deformable, sturdy box that is well ventilated. Styrofoam boxes can work well with adequate ventilation, and this material is particularly good for retaining heat. However, most airlines consider styrofoam by itself to be unsatisfactory because it's easily crushed unless reinforced (e.g. with wood). For small hatchlings, soft material loose within the container can be used to provide some protection from knocks, although some materials such as paper can be unsuitable because when damp they'll create a soggy, unhygienic mess that the animal will not appreciate. For larger animals, well-ventilated boxes and crates can be used together with suitable insulation. Another method is to use a sturdy, ventilated plastic tube. The crocodilian can be slid into the tube and the ends secured with plastic or wooden capping, securely fastened. Soft padding should be used to line the box or tube capping as the crocodile will, unless physically restrained, rub its snout against the sides in a valiant attempt to get out.

For larger animals, it is a good idea to secure the jaws with strong elastic material or tape (left) to ensure safe removal from the box or tube. Be very careful to ensure that any tape or band does not cover the nostril button at the tip of the upper jaw! When the mouth is closed, the nostrils are the only way that the animal can breathe,

and if covered it will suffocate in a couple of hours or much less. Improperly secured bands have been known to slip over the nostrils, resulting in a dead crocodile. Another way to minimise stress is to ensure that the animal cannot see anything - either by ensuring the container is totally dark, or by covering the closed eyes carefully with appropriate, soft material secured using tape. Larger animals can be immobilised for their own safety by tying the legs together at the sides, being careful not to over-tighten any such restraints. Very large animals (over 6 feet / 1.8 metres) may require sedation during transport, and for this you must consult a qualified veterinarian.

Consider also that once inside the box or tube, the animal can no longer thermoregulate effectively. Therefore, ensure that it isn't exposed to excessive cold or heat during transport, remembering that most crocodilians prefer a body temperature of around 29 to 32 degrees C (84 to 90 F). Most species can tolerate a drop in body temperature to the low 20s Celsius (low 70s F) for a short period, but prolonged excessive heat above 38 Celsius (100 F) (core body temperature) can be fatal. Ensure that, according to USF&W regulations, there is at least a 3 cm (1.2 inch) space above the animal to allow adequate airflow.

When transporting a crocodilian, always mark the carrying container appropriately (e.g. "Live reptile", or the name of the species) with large lettering - if someone has to open the container, they need to be forewarned of its contents. Other instructions should also be used (e.g. "Avoid extreme heat & cold", "Keep out of direct sun", etc).

The primary purpose of whatever method you use to house the animal for transport is to ensure that it reaches its destination uninjured, in good health, and with the minimum of stress.

7- Others :

Are there laws against keeping crocodilians?

Yes there are, and there can be several to consider. Firstly, all crocodilian species are listed under either Appendix I or Appendix II of CITES (the Convention on International Trade of Endangered Species of Wild Flora and Fauna). Species listed under Appendix I are severely restricted in international trade because they are usually (but not always) endangered or critically threatened in the wild - CITES is a trade agreement, not a firm declaration of a species' conservation status. However, only captive bred specimens of Appendix I animals (which are therefore considered in the same context as Appendix II animals) may be available in some cases. Appendix II animals, which encompass most crocodilian species including caimans, can be traded between countries with the possession of the appropriate export and import permits. Once within a county, CITES no longer applies for trade within that country. CITES import and export permits are no longer necessary for trade between the member states of the European Community.

What about hybrids? It is true that some species will hybridize with others, and this is something they do in the wild as well as in captivity. In the pet trade, some people believe that hybrids are exempt from CITES classification, or that they are classified as CITES Appendix III and can be more easily traded. This is not true! Hybrids take on the CITES classification of the most endangered parent. Breeding an Appendix I Philippine crocodile with an Appendix II mugger crocodile (if such a thing were possible) would give you an Appendix I hybrid. This is only relevant to international trade, however. Laws within countries may or may not recognise hybrids.

Crocodilians such as caimans are often classed as "dangerous reptiles" for fairly obvious reasons, although the legality of keeping a crocodilian depends upon the country or the state in question. For example, in the UK it is illegal to keep a crocodilian in captivity unless you have an appropriate permit. Such permits can be obtained, but first it is necessary to prove to the local council that you are capable of keeping such an animal. You must have suitable accommodation that is both escape proof and secure, you must be experienced in handling the animal, and you must have a thorough grasp of its husbandry requirements. You're then required to pay a fee for a permit that must be renewed each year pending successful examination of your animals by a qualified vet. In the US, the situation is more complex. In some states, for example, it is illegal to sell crocodilians, but it is legal to keep them. In others, they are classified as dangerous animals and require a special permit to keep them. In some cases, city and/or county statutes prohibiting the keeping of crocodilians supersede any state regulations. The difficulty of getting a permit depends on the state. California, for example, does everything it can to discourage anyone from keeping a crocodilian. Some states are more relaxed, but the situation in these states may well change in the near future as controls on keeping reptiles (particularly those perceived as being dangerous) are tightened. The best solution is to check with your local authority on the laws concerning the purchase and housing of any crocodilian species. A list of contacts is presented in Appendix II. US citizens may also wish to consult the book entitled "A Field Guide to Reptiles and the Law" by John P. Levell.

Remember that if you do not have the appropriate permits that your country or state demands, whether you are interested in trade or captive husbandry, you are breaking the law. The hassle of obtaining a permit is nothing compared with the hassle if you're found without one. In the US, possession of a crocodilian without appropriate permits may range from a class 1 misdemeanour in some states (punishable by a maximum of 1 year in jail and a US$2500 fine) to a class 4 misdemeanour in others (punishable by a US$100 fine). Regardless of the punishment, the animal is confiscated and normally destroyed. Also, most veterinarians will refuse to deal with you unless you can present the appropriate permits.

Is it possible to tame a caiman or other crocodilian?

In theory yes, it is possible to tame a crocodilian. However, it is exceedingly difficult, and most animals will only become moderately calm at best. Many people have tried to tame their animal, with limited success. The only crocodilians that I've seen which would be described as "tame" had been handled every single day of their lives for extended periods of time. Even then, the animal is still capable of inflicting a serious bite, and the feeding reflex of a crocodile can be very difficult to inhibit. Individual temperament varies a lot between animals, and some are certainly calmer than others. Some species also tend to be more docile than others, but all are capable of giving you a nasty bite when they're in no mood to be approached. Never buy any crocodilian on the pretence that you will be able to tame it - disappointment will probably be the most likely outcome, with only bite scars to remind you of your attempts.

The Number One Rule when dealing with any crocodilian is to never drop your guard and completely trust the animal. Always be aware of what it is capable of, and respect both its bite and its speed.

Are crocodilians capable of learning?

Yes, crocodilians can learn very well. You won't be able to train them to fetch your slippers, but given time they can recognise individual people and react to them in a positive or negative manner. They can learn events, such as what leads up to feeding time, or enclosure cleaning time. Be aware, however, that this can work against you if you're not careful. For example, if you feed your animal the same way day after day it will learn the routine and know when to expect food to appear. If you accidentally duplicate parts of this routine when you clean the enclosure, the animal may think it's about to be fed - and getting bitten by an over-enthusiastic caiman is a very likely possibility.

In the wild, crocodilians display a wide range of social and sometimes even cooperative behaviours. The creature regarding you from behind the glass is smarter than you think.