Melissa Kaplan's
Herp Care Collection
Last updated January 1, 2014

Frequently Asked Questions About Alligators and Their Kin

©1996 Robert Gruen

Introduction
Alligators, caimans, gavials, and crocodiles belong to Family Crocodylidae. Although this family has existed since the upper Triassic Period, over 200 million years ago, reptiles which can definitely be classed as modern alligators, caimans, gavials, and crocodiles only appear in the fossil record about 80 million years ago. Today, Family Crocodylidae contains three subfamilies: Alligatorinae (alligators & caimans), Crocodylinae (crocodiles), and Gavialinae (gharials or gavials). A fourth subfamily, Tomistominae, containing a single species, the False Gharial, Tomistoma shlegelii, has been proposed.

The American Alligator (Alligator mississippiensis) & Chinese Alligator (Alligator sinensis) are commonly seen in zoological parks, but only the American Alligator is frequently encountered in the retail herp trade. Various genera and species of caimans are sometimes available along with a few Dwarf Crocodiles; often they are mislabeled into Genus Alligator.

The American and Chinese alligator are unusually tolerant of cold conditions. Both have been found frozen in ice in the northerly parts of their respective ranges.

Crocodiles are rarely kept as pets. Yet just two species, the Nile and Indopacific crocodiles (Crocodylus niloticus & Crocodylus porosus respectively) regularly take human prey. In the famous Mugger Pit at Karachi, Pakistan, the public strolls daily among hundreds of healthy adult (>13 ft.) Crocodylus palustris without incident.

This entire family is CITES-listed (Convention on International Trade in Endangered Species). The American Alligator is the only member to have recently undergone a dramatic population resurgence because of human protection, but restrictions on its capture still remain in effect. Because of the tenuous status of this ancient family, no member should ever be taken from the wild without appropriate authorization, and buyers should exercise due diligence with respect to imported animals.

Private ownership of alligators, caimans, crocodiles, and gavials is subject to widely differing laws from State to State. While some States may require extensive licensing, including inspection of caging and certification of owner qualifications, others permit virtually unrestricted ownership. In addition, city and regional ordinances may impact those who wish to keep these reptiles. Thus, it is imperative that prospective owners of crocodilians thoroughly check the range of pertinent legislation before actually obtaining any animals. Please remember that keepers of conspicuous (and sometimes dangerous) herps owe a special obligation not only to their own communities but also to herpetoculture as well. Always know the law fully, and obey it!

How do I distinguish alligators, caimans, gavials, and crocodiles?
While most alligators, caimans, gavials and crocodiles look similar to the casual observer, there are very distinct differences in both appearance and temperament among these reptiles. Crocodiles are not too difficult to distinguish. A crocodile can be differentiated from an alligator or caiman by its prominently protruding fourth tooth on the lower jaw. With alligators and caimans this tooth is hidden inside a socket on the upper jaw. The African Dwarf Crocodile (Osteolaemus tetraspis) has an extremely short snout, and the entire animal never exceeds 6 feet.

Alligators and caimans appear rather similar to each other, but they can be told apart easily if you know what characteristics to look for. The alligator has a broad rounded head, while the head of a caiman is slightly more pointed. Spectacled caimans have a small bony ridge on their heads (infraorbital bridge), and caimans generally have much shorter tails than alligators.

Gavials (or gharials) are easiest to identify because of their more slender overall structure and highly elongated muzzle studded with numerous interlocking teeth which project slightly outward. The upper tip of the snout is bulbous. Gavials are specialized fish-feeders, rarely venturing to sample other prey.

How fast do they grow?
The growth rates of these reptiles will vary according to the conditions under which they are raised. It has been shown that optimum growth is achieved if the animal can reach a warm temperature (~89F) and is provided with a steady, adequate food supply. In general, expect about one foot per year of growth for juveniles under ideal conditions. Growth rates will slow as the animal gets older.

Commercial alligator farmers in Florida and Louisiana use growth-forcing techniques wherein the reptiles reach 6'-8' in two years or less. The animals are kept on heated slabs in dark rooms year-round and are power-fed daily. Such techniques are unnatural and unhealthful; they are exclusively employed to promote faster "harvests" of gator products and should never be adopted by the herpetoculturist.

Alligators will usually grow to a length of 7'-15' (with males generally averaging about 4' larger than females) and can weigh more than 1300lbs. Caimans generally remain smaller and will only grow to an average length of 4'-8'. Smaller still is the Dwarf Crocodile, as noted above. The most diminutive member of the family is Cuvier's Dwarf Caiman (Paleosuchus palpebrosus) whose maximum recorded length is only 5'.

What are their temperaments?
As a rule, you should exercise caution around any of these reptiles. They are not domestic, and a bite can inflict serious injury. Generally the crocodile is the most aggressive, followed by the caiman, and then the alligator and gharial. There may, however, be notable exceptions. For example, the rare American Crocodile, Crocodylus acutus, is reported to be temperamentally closer to the American Alligator than its nearer relatives.

In addition, the African Dwarf Crocodile is known to be exceedingly timid and docile. These traits probably account for its increasing popularity in the pet trade. Crocodilians will attack in self-defense, to obtain food, and to protect their young up to two years after birth. Indeed, the outstanding parental care they afford is unique among herps and (along with certain anatomical features) illustrates the close alliance of this family to birds and, ultimately, dinosaurs.

The psychological orientation of alligators is interesting. It appears that alligators tend to regard humans as animals larger than themselves and thus will not generally attack a human without provocation.

However, they will certainly look after their interests as outlined above, and a small number of accidents have occurred when their predatory or protective instincts were inadvertently triggered.

Caimans are generally very aggressive animals. If you are interested in keeping one for a pet, I would definitely advise starting with a small (9-12") animal. I have seen only one tame caiman in my life, and it only got that way through regular handling --at least 1 hour/day! I have seen many other caimans which were some of the meanest animals I've ever encountered. My caiman is now almost four feet long and requires two people to responsibly perform maintenance on his room.

 What do they eat?
All alligators, caimans, gavials, and crocodiles are carnivorous. In the wild, each depends upon a somewhat different selection of prey from its local fauna.

For captive specimens, diet should vary with the size of the animal and the availability of prey. Small captives will do well on small animals (e.g., goldfish, insects, or mice.) As the reptile grows, its diet should change from mice to rats to rabbits, chickens, and other suitable larger prey. Commercial "alligator chow" is also available. It's prudent to supplement meals with added calcium. Gavials will dine exclusively on fish.

Caimans are usually enthusiastic eaters, consuming almost anything that moves, though they are also "shy" about eating in busy places or in front of large groups of people. Small caimans will do well eating small goldfish along with mice or pinkies. As a caiman grows, the diet should be primarily mice and later rats--though (s)he might appreciate an occasional goldfish.

I recommend feeding pre-killed prey to alligators and crocodiles and have found that, when provided with a warm environment, they will rarely refuse food. Crocodilians which will not feed are either sick or maintained at an improper temperature.

How are they housed?
Housing requirements for most species of alligator and crocodile are very similar. Of course, a large outdoor pen with a small pond or pool is best, but I will describe an indoor setup since many people do not live in climates that are sufficiently mild year-round.

A popular notion is that these animals are primarily if not completely aquatic. This is not the case. With the possible exception of gavials, crocodilians require at least as much dry land as they do water. However, they do require enough water to efficiently thermoregulate and wash food down their gullets. They also need a large lighted and heated area with at least one good basking spot.

Many crocodilians experience stress if constantly maintained above the mid-80s F. Conversely, most refuse to feed if forced to live much below the mid-80s. As with other herps, only God and the animal know exactly what temperature (s)he should be at any given time. Consequently, housing should incorporate a reasonable temperature gradient across the 80s F. to allow uninhibited behavioral thermoregulation.

A suitable enclosure is a walkway set within an area where both length and width are each a few feet longer than the specimen. A 5' or 6' kiddie pool makes a nice water source (at least for a while). The water should be kept fresh with a large, high-quality aquarium filter. In this context a "high-quality" filter means that it will keep the water in constant motion so there is no danger of stagnant conditions. This is healthful for the reptile and ultimately means much less maintenance for the keeper. I would also recommend hanging a few 250w heat-lamps around the enclosure. In my own setup I use one to warm the pool water and another to provide a basking spot. Make certain these lamps cannot be struck by splashes though, as cool water hitting the hot glass will cause them to explode!

Since caimans are very hardy creatures, an aquarium setup for these animals can be designed to suite your taste/budget--at least for a while!

Keep in mind that all caimans require the following:

1. Enough water to move around in and submerge. Water should not be very warm, but it should not be extremely cool either. Also keep in mind that the water must be kept in motion with a filter of some sort to prevent stagnant conditions.

2. A dry area to escape from the water when (s)he wants. They tend to spend more time in water when young, increasing their time out of the water as they grow.

3. A heated basking area allowing him/her to regulate body temperature as required.

The aquarium for a caiman should optimally be at least the length of the reptile in depth and 2 or 3 body-lengths long. As a caiman grows, (s)he will eventually require either a room of its own with a swimming pool or a very large aquarium. Mine has a room in the basement that is 8.5'x8.5' with a 5' kiddie pool, and he is quickly outgrowing that--mostly because of his aggressive nature!

How long do they live?
An important aspect of caring for a reptile like this is giving serious thought to how long you will have to be responsible for it. Remember that a large (1000+ lb) alligator or other crocodilian cannot be readily sold or given away, and your once "cool" pet (that you bought when you were 25) may be a bit more difficult to accommodate adequately 40 years later.

As a general rule the expected lifespan of American Alligators is about 50 years, at which time they often begin losing teeth and showing signs of senility. The longest-lived captive alligator on record died at 66 years at the Adelaide Zoo (Australia) in September, 1978. Henry, an African Dwarf Crocodile brought to the Lincoln Park Zoo (Chicago, Illinois) in 1940, is, at last report, still alive. It is assumed most other crocodilians have similar lifespans, however some large Nile Crocodiles (18+ feet) are reputed to be 100 years old or older.

In February, 1995, the Associated Press reported that Kolya, a ten-foot crocodile (species unstated), had passed away at Russia's Yekaterinburg Zoo after residing there continuously since 1914. Asserting that records indicated Kolya had arrived as a fully-grown adult, Curator Natalya Bobkovskaya declared the reptile was between 110 and 115 years old at the time of his demise. 

Some Personal Observations
I purchased Cyan, my male caiman, over two years ago when he was still quite young and his total length was less than 15 inches. Over that period I've had the opportunity to note the habits and behaviors of this fascinating animal as he grew to his current ~40 inches.

His most routine habit is basking. I regulate his day/night cycle with a pair of 250W heat lamps connected to a 24-hour timer. During dark hours he spends all of his time in the pool, not emerging until about 2 hours after the lights have kicked on, and things have warmed up slightly. He then sits on his favorite basking spot (always facing the door to the room), remaining there for hours. Once he's happily basking, there are few things that will move him away (excluding brief dives into the pool to cool off).

One of the things that will distract him is food. He's generally an enthusiastic eater and can be somewhat aggressive when it comes to feeding, though he can also be quite shy depending upon who is there. For example, if I feed him by myself (which I usually do) he will take the food immediately, eating it while I watch. After he has eaten two or three rats though, he will take subsequent rats behind his pool, where you can no longer see him from the door, and eat privately. What's more, he is very shy about eating in front of people. He will almost never eat if there are three or more people at the door to watch (or even if he hears a lot of noise), and he will often refuse food if there is just one other person there with me. Instead, he will take the food and either go behind the pool to wait or simply go back into the water.

He displays a similar personality during maintenance. For example, if I go in to clean the room alone, he is very aggressive. He will watch me closely, hissing or jumping toward me if I get too near. However, if I bring someone else to watch while I clean the room, he will remain in the water watching both of us. Perhaps he doesn't quite know how to deal with more than one "intruder"!

These are just some regular behaviors I've had the opportunity to observe.

A final note on where to obtain such critters: There are a few breeders and dealers who supply caimans (and other crocodilians); consult the ads in quality herp publications like The Vivarium, Reptiles and Amphibians, etc. Caimans regularly show up in pet stores in states which do not have restrictive legislation against them, thus you should be able to get a healthy caiman from almost any reputable pet shop. Our pet store here in town almost always has one or two. You local herp club might also be able to help, if your pet store doesn't carry them. As with purchasing any herp, make sure the supplier is taking good care of all of their reptiles, as the care they are receiving will affect the eating habits and overall health of the animal you purchase. 

How can I add something to this FAQ?
We are grateful to Kevin Nunan and others who have made valuable contributions and/or corrections. In our continual effort to improve this FAQ we encourage anyone who would like to make suggestions or contribute information to please contact either anacimas@! cerf.net or Robert.Gruen@! sdrc.com

Related Articles:

Adam Britton's Crocodilian Biology Site

Note: Caiman are no longer legally sold in California. There are still some individuals who have caiman from the time they were legally sold. All other crocodilians are illegal to privately possess in California.