8. HEALTH CARE
6.1.1 What does a caiman eat in the wild?
Wild caimans are opportunistic - that is, they'll eat a wide variety of different prey items as they become available during different seasons. The size of prey items depends on the size of the caiman, with hatchlings eating small insects, fish, amphibians and reptiles, and larger caimans eating larger versions of these prey. As they grow, caimans include mammals, birds and larger reptiles in their diet. Adults also include a fair number of crustaceans and molluscs (e.g. freshwater crayfish, snails) in their diet, which their broad, powerful jaws are especially adept at crushing. In many crocodilian species, adults will readily cannibalise young crocodiles.
Most other crocodilian species follow the same kind of dietary progression, from small insects and fish when young, to a wider variety of larger prey as they grow. Slender-snouted species tend to eat more fish, and broad-snouted species often include hard-shelled prey in their diet.
6.1.2 What can I feed my caiman in captivity?
As caimans and other crocodilians normally take a wide variety of prey items in the wild, they will eagerly eat almost anything that is put in front of them in captivity. This means that you have to ensure your animal is getting a balanced diet. Here are some guidelines for feeding your caiman.
Getting a balanced diet is all about making sure the body gets all the protein, carbohydrate, fibre, vitamins, minerals and other goodies that the body needs to survive. As crocodilians tend to eat whole animals, they often get the complete package deal in one meal - protein from muscle, calcium from bones, etc. It's a good idea to follow this formula in captive animals. Many owners have a habit of feeding pieces of lean meat to their animals. Whilst lean meat is perfectly ok as part of a varied diet, it should be supplemented with additional calcium from other sources to avoid calcium deficiency. Calcium deficiency can take months to show itself as a problem.
A good diet, then, is one that provides your caiman with a reasonable degree of variety. Many caiman owners like to feed their animals fish, and there are any number of different species you could use such as herring and perch, although some fish are better than others in terms of their nutritional content. Several owners keep goldfish free-living in their caiman's water area just in case their animal gets hungry, although there are better fish that could be used. In this case, you'll need to use an air stone and water pump to oxygenate the water or the fish will die quickly. The fish themselves also need to be fed regularly. However, be warned! There are two big disadvantages with feeding fish. The first is that fresh and frozen fish often contain large amounts of the enzyme thiaminase. Freezing appears to increase concentrations of thiaminase in tissue, so frozen fish should be treated with some caution. Thiaminase destroys the vitamin B1 (thiamine) and thus if you're using fish ensure you use a vitamin B1 supplement, or you heat the fish (80 degrees C for a short period) to denature the enzyme. Not all fish contain thiaminase - eg. ocean perch are a better choice. The second problem with feeding fish, particularly oily fish, is the possibility of vitamin E deficiency (steatitis). This is a common disease in crocodilians fed a very high proportion of fish in the diet, so be aware of its implications. The high proportion of unsaturated and rancid fatty acid that is present in fish (particularly if it's not fresh) rapidly accumulates in the caiman's body if you feed little else. Oxidation of these fatty acids (which is prevented by the presence of vitamin E, an anti-oxidant) leads to the formation of ceroid pigment that results in necrosis of fat cells and serious inflammation. Fatty build-ups and nodular lesions develop throughout the body cavity and within the extensive subcutaneous and intramuscular fat pads. If this sounds nasty, you're right - it can be fatal to the animal. Increased variety in the diet is the easiest way of avoiding this problem.
Caimans and most species of crocodilians will readily take a variety of insects when younger. You can either purchase such insects from most pet stores or catch them yourself using a light trap or fine net - but make sure you collect them from an area free of insecticides and other chemicals. Ensuring that the insects are healthy and well fed means that your caiman will be eating good quality food. Mice also make good food items, small pinkies being suitable for small caimans, and the adults for larger animals. Rats are also suitable, and like many of these foods are commonly available from pet stores or other outlets. Other food items which can be fed to add variety include pieces of meat (pork, chicken, beef - which can be fed on the bone in larger adults), earthworms (not the worms used commercially in composting - they're poisonous to small crocodilians), snails, freshwater crayfish, spiders, even frogs and small lizards. Of course, some caimans are fussy and will turn their noses up at certain food items. One owner points out that his caiman dislikes squid, and isn't very keen on butterflies - possibly because of the large, powdery wings. There are plenty of alternatives, however, so rejection shouldn't normally be a problem.
Be careful feeding young hatchlings - unlike adults, their digestive systems are more fragile and cannot handle everything you throw at them. Over-feeding insects, particularly those with hard, chitinous exoskeletons (e.g. black crickets), can block the gut as the chitin isn't broken down easily. One of the authors recommends squeezing soil out of earthworms before feeding young hatchlings, otherwise the coarse grit may damage the intestine.
Although feeding whole prey may be natural, there are alternatives. For young hatchlings especially, many owners recommend finely chopping or mincing whole prey items and feeding them on a small dish. This way, the food will break down in the stomach far more quickly, and digestion will be much more efficient. Crocodile farms always feed ground food to hatchlings to maximise food conversion rates and overall health. You can switch to whole prey as the animal grows in size. The disadvantage of feeding ground food is the considerable mess that is possible if your caiman decides to walk all over its food and drag it into the water. Be prepared to clean the tank and water every day if you use minced food.
Commercial feeds are available for both hatchlings and adults alike. These are typically a pelletised feed that the animal takes either on land or in the water. Not all species will take pellets, although recent research has discovered that appropriate ingredients to encourage feeding may be required for particular species. Pelletised feeds have many advantages, such as being easy to store, far less risky to offer to the animal, and they usually don't cause a mess in the enclosure. By all accounts, they appear to be nutritionally complete in the long-term.
6.2 How often does a caiman need to eat?
Caimans should be fed approximately three to four times a week, or once every two days while they're young. As they get older, and the food they're given gets larger, the frequency of feeding can drop to two or three times a week. Temperature can also influence both the caiman's desire to eat and its overall digestion rate. It is rare for a caiman to refuse any food that is offered, except for breeding animals during short periods in the year. Females full of eggs, for example, will eat much less simply because there's little room left in the abdomen for food!
It is possible to overfeed a caiman as well, with gout being the typical result due to excessive protein intake. Dehydration and low temperatures also exacerbate gout. Excess fat in the diet will result in extensive subcutaneous and intramuscular fatty deposits. It is therefore important to monitor the animal's general body condition and alter your feeding schedule accordingly. Incorrect diets can be improved before affecting your caiman's health, but all too often people let their animals reach a terrible state before seeking veterinary attention.
6.3.1 How do I give food to my caiman safely?
One of the best ways of getting bitten by a crocodilian is being careless while feeding it (snake owners use the acronym SFE - "stupid feeding error" - to remind them who made the mistake that led to the bite). The caiman's behaviour during feeding time will vary between individuals, and also on the size of the animal. Small animals tend to be quite wary about feeding when they're being watched. They will frequently leave the food until the owner is out of visual range, or even wait until after dark before eating it. As the caiman grows and learns that the owner is not a threat, it will become bolder, often trying to take the food as it's being offered. If you're holding the food in your hands while offering it, then your hand is viewed as fair game. This is also a bad idea because every time you place your hand inside the caiman's enclosure (even if it's not feeding time) the caiman will look upon it as a feeding opportunity, which clearly isn't desirable.
Colin Stevenson points out how athletic caimans can be: "People new to this should be aware that caimans will jump for the food, and since they tend to close their eyes as they snap their mouths shut, they aren't always accurate! Mine will jump almost out of the water to get their food - in fact, if I held the food high enough, their bodies would clear the water!"
One way of making feeding safer is to offer food using a pair of tongs, or a similar device. One suggestion is to use a piece of piano wire, bent into an appropriate shape. In this way, your hand goes nowhere near the caiman's mouth, and makes it more likely that the caiman will take the offered food from the implement. If the caiman doesn't want to take the food immediately, it should be left on the land area, preferably on a shallow dish of some description - especially if you're feeding pieces of meat. Placing food in the water is also possible, although it can make quite a mess in there, especially if the animal bites into it and causes blood and other fluids to splash into the water (and all over the glass and furnishings!).
6.3.2 Should the food be whole, or in smaller pieces?
That depends on the size of the caiman. The animal should be able to comfortably swallow the prey item that's offered to it. If it's a little too large, the caiman will bite and crush it to reduce its size slightly. However, if the caiman still can't swallow it, the next stage is a quick flick of the head while holding onto one edge of the prey. This usually tears the prey into two, and can be very messy! If the prey is far too large, or if you're holding onto it, the caiman may even try to spin its body axis to tear a piece off. Again, this may be spectacular to watch, but it only serves to make a huge mess in your enclosure. Therefore, smaller pieces are a better idea. Another point to consider is that feeding whole furred prey items will fill your caiman's stomach with indigestible hair. This isn't a problem for the caiman, as these hairballs are regurgitated fairly frequently, but it can be messy to clean up. Some owners therefore prefer to skin mice and rats before feeding to avoid this regurgitation, although some feel that the caiman may derive at least some nutritional or digestive benefit from the fibre and that it's best left on. As mentioned earlier (see 6.1) you can mince the food and present it on a dish. This aids digestion of the food in smaller animals, but can cause a big mess in the enclosure.
6.3.3 Should I feed live or pre-killed food?
Prey items can only be fed live to animals in those countries that allow it. The feeding of one live vertebrate to another is illegal in the UK, for example, unless the animal refuses to feed on pre-killed prey items. In most cases, your caiman will not have a problem eating pre-killed food - in fact they will try and eat anything that enters their enclosure. If you stock the caiman's water area with goldfish, then clearly these will be live until the caiman gets hungry enough to eat them. It is generally a bad idea to put live adult mice or rats into an enclosure with a caiman, as they are actually quite capable of giving smaller caimans a nasty nip while trying to defend themselves (in vain). The caiman will also do its best to catch the animal, even if that means destroying half of its enclosure. Most owners agree that it's not worth risking injuries to your caiman in order to feed live prey when pre-killed prey will suffice.
6.4 What's the earliest age that my caiman can eat?
All hatchling crocodilians contain a fairly substantial yolk sac which will sustain them for several days after hatching, or even a few weeks in extreme cases. However, all hatchlings come equipped with tiny, needle-sharp teeth and they can begin to feed within a very short period of time. You should start to offer food within the first week after hatching.
6.5 What about vitamin supplements?
It is a good idea, especially for smaller, growing animals, to use a small amount of multivitamin and calcium powder (calcium carbonate) with the food to make up any shortfall in their daily requirements. Excess supplementation can be bad, however, and such supplementation is normally only required for juveniles, where calcium may be less readily available in the diet. Juveniles get very little calcium from insects, for example.
If you're feeding primarily frozen food, you'll need to add vitamin B1, which can be found in brewer's yeast and in stand-alone thiamine (B1) vitamin supplements. This is an essential vitamin, but the enzyme thiaminase (found in frozen fish) and the freezing and defrosting process destroys it. Steatitis is another problem resulting from a diet high in oily fish, and such a diet should be avoided. Symptoms can be addressed with the addition of vitamin E.
6.6 Is there any danger of parasites from wild-caught foods?
There may be a small risk of ingesting parasites when using wild-caught foods such as mammals. Snails also harbour parasites that can infect caimans. Buying foods from appropriate outlets may be a safer option.
6.7 Why does my caiman sometimes ingest small stones?
All crocodilians eat stones and rocks in the wild - they're referred to as "gastroliths", and the process is called "geophagy". These stones sit in the animal's stomach, probably for many years, and help to break down food by a mechanical grinding action - a little like a bird's crop. They may also help to weigh down the caiman a little more in the water and therefore act as a ballast. In captivity, crocodilians should benefit from the presence of stones in their guts - it will help them to digest their food a little better if you feed whole animals, especially those with hard bones or shells. If you provide many small stones or pebbles in the enclosure, then the caiman can ingest any which are required. Be cautious of this habit, however, as the animal will resort to ingesting just about anything - especially if there are no suitable stones available. One owner resorted to surgery on his caiman after an x-ray revealed that it had ingested three aquarium suction cups, which occupied most of its stomach capacity.