Michael's Zoology Information Site - Animal Facts - Questions and Answers about Animals

Here I've provided an area where I post questions and answers that people have asked me about animals. Do you have a question about an animal? Please send me an email. Feel free to ask anything, from animal behavior to identification.

Saltwater Crocodiles: I have read some material about Saltwater Crocodiles, but I don't really have a clear picture of how much time they spend in the water, or how far they can swim. Can you help me?

Saltwater crocs can swim a long ways, and inhabit coastal areas and rivers that empty in to the seas, from southern Africa all the way to Australia. They are commonly found off the coast of Australia, and in the archipelago between Australia and southeast Asia. Also coastal India and Africa. It's unclear how far out to sea they venture, but they have been seen by fishermen swimming hundreds of miles from the coast. Conversely, like many other reptiles, they can spend long periods in more xeric conditions. It's not unusual to find a saltwater croc on dry land hundreds of miles inland from the coast.

The saltwater crocodile is able to inhabit saltwater because they have glands that secrete salt, thereby keeping the salt level in their blood lower than the salt level in the ocean waters. They are (as far as I know) the only crocodilian species that can do this. They are at home in both fresh and salt water. Most other crocodilians inhabit major river drainages, and stick to freshwater habitats.

Crocodile and Alligator relationship: I'm curious why alligators and crocodiles split evolutionarily, yet maintain some overlapping habitats, whereas other members of each group are dispersed throughout the globe.

Alligators are crocodilians, just a separate group like caimans or garials. Interestingly, there are only two alligator species in the world, the American alligator and the Chinese alligator. They are sister species, with their ancestor occupying north america and asia millions of years ago when the area of alaska and the bering straights were a connected, tropical land. When the climatic barrier formed between North America and Asia, the two alligator species evolved independently.

American Alligators and the Endangered Species Act:I am looking for a source of population survey data on the American Alligator population past and present. I understand that it was on the endangered species list from 1967-87. The school assignment is to gather raw numerical data. The student is to create the graph him/herself on the computer. There is a great deal of prose on this topic, but I am having trouble finding "the numbers." Any ideas? Thanks!

Yes, I do have an idea. In order for the Alligator to have been listed under the Endangered Species Act, there had to be a U.S. Fish Fish and Wildlife report, published by the Department of the Interior, which explained exactly why the species was being listed as "Threatened" or "Endangered." This report will include the specific numbers you are looking for. You might have a little difficulty in obtaining this report, however. Here are a couple of ways to try: You might be able to find it through the library or inter-library loan. You would probably need to know the exact title of the report in order to obtain it this way. You should be able to find the title of the report online, or if you call the publisher of the report. Speaking of the publisher, you (because you are a citizen of the United States) are entitled to a free copy of that report if you can locate the publications office at the Department of the Interior. I have a phone number for the Publications Unit, U.S. Fish & Wildlife Service, which might work, it's (703) 358-1711. Also, I have a report published by the Department of the Interior on North American tortoises, which has a phone number listed for the National Techical Information Service: (800) 553-6847. As a last resort, you could contact a U.S. Fish & Wildlife agents who work in management areas inhabited by alligators. They may actually have a copy of the report they could photocopy and send to you. Again, you might be able to find such agents through an online search.

Wolf predation: I'd like to know how a predator like a wolf would kill its prey. How would it hunt, attack, kill, and eat? I'm particularly interested in how it might attack and eat a stationary, domesticated animal like a cow, sheep, or pig. What parts of its prey does a wolf eat? Does it drag its victim away to eat it?

OK, I'm not a specialist on wolves, but I have learned a few things about them. Wolves typically hunt in packs, but hunt solitarily as well. When hunting in packs, they'll go after prey like elk, moose, or deer. A pack (which can range from 3 to 10 animals) will try to single out a weak animal from the herd, which is usually a calf or fawn. Several of the wolves may try to divert the mother from the young animal while others run down the selected prey. This all usually happens on the run. The wolves attacking the prey grab it any way they can, working as a team to take it down. When it is taken down, one or two wolves will bite at the throat to suffocate the animal.

The wolf pack is a highly social group, and cooperation is a key ingredient to successful hunts. The wolves may communicate through barks, growls, and body language throughout the hunt. This communication is somewhat sophisticated. The hunts are led by the dominant male or female of the pack, or other successful and experienced hunters. When a prey item is killed, the pecking order within the group determines who will eat first and the most. Usually the alpha male and his mate eats first, followed by successively subordinate animals. Pups or young wolves may be allowed to eat ahead of subordinate adults if they are the offspring of high ranking wolves.

During a feast after the kill, the wolves exhibit some really intense body language as they reinforce the pecking order. At this time, a lot of snarling, pulling back the lips to show teeth, growling, and hair-raising goes on. This continues as the feeding begins, and throughout the feeding period. Dominant wolves may have to chase away subordinate members if they are really hungry and there isn't much to eat. A very large prey animal will generally result in a relatively calmer feeding session. The hindquarter region is typically the preferred spot to begin eating, although shoulders and forelimbs are high-quality parts as well. High ranking wolves will typically have their pick with the higher quality parts. The prey animal is usually eaten at the kill site, although parts may be dragged to a den area if very young pups cannot make the hunt. I would expect that wolves hunt in similar ways when hunting domesticated livestock, and I would expect livestock to behave like wild animals when they are being pursued.

Play is a necessary part of growing up for young mammals. It's a way for them to socialize, establish a dominance hierarchy, and most importantly, to develop muscle coordination and skills that will allow them to survive on their own someday.

Marine species: How is it possible for seals, whales, and some fish to live in salt water?

Any animal that lives in the ocean, or is intimately tied to the ocean, has to deal with one problem: keeping the salt level in the blood and other tissues lower than the salt level in the ocean. If they could not deal with this problem, osmosis would cause water molecules to go from an area of low potential (the body) to an area of high potential (the sea water), and the animal would shrivel up and die from dehydration. So the way sea creatures solve this problem is by excreting as much salt from the body as possible, and by conserving water. They accomplish mainly through very powerful kidneys, which conserve water and concentrate the urine, and through specialized glands that excrete salt. These organs require a considerable amount of energy, and a good deal of the resources (food energy) is allocated towards the activities of these organs.

Actually, lemmings don't commit suicide. It's a common misconception, and a variety of explanations have arisen to 'explain' the apparent mass-suicides. What actually happens among lemmings is a mass dispersal event. Lemming populations typically fluctuate in three- to four-year cycles. When the population reaches a critical maximum, the organisms disperse in all directions in order to lessen the amount of competition for food between them. Hundreds or thousands of the critters spread thoughout their habitat. On at least one occassion, people observed lemmings jumping off a cliff during a dispersal event, and concluded that the animals were committing suicide. I can assure you that the lemmings did not have suicide on their little minds, they were simply dispersing to a new habitat. They just ran into a dangerous situation, unwittingly...

Balancing flamingos: Why is it that pink flamingos can stand for so long on one leg and keep their balance without falling over?

Next time you see a pink flamingo, look at how long their toes are. When they stand on one foot, the extra-long toes of that foot are splayed out, giving the animal incredible stability...kinda like if you were to put on snowshoes, you'd find it easier to stand on one foot with them on.

The best thing you can do for a rattlesnake bite is 1) do not get excited, remain calm so that your heart rate does not increase...this will keep the venom from going through your bloodstream quickly. 2) don't try to treat it yourself - get to a hospital ASAP. If you try to fix it yourself, you are only wasting time. The best thing to do is to remain calm and get to the hospital quickly so that they may administer the anti-venom. Keep the affected area below the heart - do not raise it! It helps to know which species of venemous snake has bitten you, so that the hospital can give you the correct anti-venom.

Dreaming: Do animals dream? How could a scientist tell that something like a chimp does or does not dream?

There's no way to tell if animals dream, but certainly, most mammals enter a stage of sleep when brain waves are similar to that of a human who is dreaming. As far as I know, this only occurs among mammals, particularly mammals with large brains. Have you ever seen a dog "dream"? they twitch their legs, bark or growl, and their eyes move. Their brain waves at this stage of sleep are very much like the brain waves of a human who is in the stage of sleep called "Rapid Eye Movement" or REM. This is the stage of sleep during which dreaming occurs. I think that other mammals dream, but their dreams are nothing like ours.

Ocelots: First, why are ocelots endangered? What are the natural predators and prey? What's the largest prey that an ocelot could kill? What is the closest living relative?

Ocelots (Leopardus pardalis) are endangered because of two reasons: habitat loss and overharvest of the species by man. These seem to be the two main reasons for any species to be endangered. Man is always changing the natural environment, and developing in natural areas. This leads to alteration of the habitat, which renders it unsuitable for habitation by sensitive species. The ocelot would be especially sensitive because it is a top predator in its habitat. The ocelot has lost habitat as its habitat has been converted to rangeland for cattle ranches. Overharvest of ocelots occurred because of their unique fur. Ocelots can no longer be harvested for their fur in the United States as they are listed on the U.S. Fish & Wildlife Endangered Species List.

Small vertebrates, primarily rodents, are the prey of ocelots, although other species like rabbits, birds, lizards, snakes, frogs, and fish may also be taken. I would suspect that the largest prey item an ocelot could take is an adult rabbit or hare. Any predator larger than an ocelot may prey on ocelot kittens, including mountain lions, bears, and eagles and hawks. The adults probably have no natural predators, other than man.

The ocelot belongs to the genus Leopardus, which includes two other species, the tiger cat (Leopardus tigrinus), and the margay (Leopardus weidi). All three species are Neotropical cats, occurring primarily in south America and Mexico, although the ocelot's range includes south Texas, a part of the Nearctic. No doubt, the genus Leopardus originated in the Neotropical region. I don't know for sure the evolutionary relationships between these three cats, but I suspect that the margay is the sister species, or closest relative, of the ocelot.

Territorial fish: I'm looking for information on fish regarding the subject of territorial behavior...

Basically, fishes, like almost all other animals, defend territories for three reasons: they defend areas within their home range so that they have control of all the resources within their home range, including food resources, refugia, and access to mates. Secondly, male fishes vigorously defend against other males when in courtship with females. And finally, when courtship has consumated in fertilization of eggs, some fish species defend a nest in which the eggs were laid.

Mollusks: Do snails ever change their shell or grow out of it, and start growing a new one? Do mollusks have a brain? How does a mollusk's digestive system work? How do mollusks reproduce?

Mollusks are a HUGE group of animals, including bivalves like clams and oysters, to gastropods like snails and slugs, to cephalopods like scuttlefish, squid and octopi. Most have a shell, which is always a part of their body and grows as the animal grows. The nervous system of mollusks range from fairly simple to very complex, and most have at least a concentration of nerves which constitutes the brain. Some mollusks, like the octopi, have large, complex brains, and are very intelligent animals. The digestive system is very similar to that of other complex invertebrates, and all other complex, multi-celled animals, for that manner. The basic components are the mouth, coelom, and anus. Reproduction in mollusks is as diverse as the group is. The common reproductive charateristic of the group is egg-laying, however. Some gastropods are hermaphroditic, that is, they have both male and female parts.

Check out the Mollusca page on the Animal Diversity Web, an excellent source for zoological information on the WWW:

Schooling fish: When fish swim in schools of fish of their own kind...how can they tell that they are with the right kind of fish?

All animals, including fish, have senses that allow them to distinguish themselves from other species. for land animals, like ourselves, sight, smell, and hearing are the most important senses. For fish, sight is probably a very important cue, but bony fish have an additional sense that allows them to detect vibrations in the water. This sensory system is located along the sides of the fish body, called the lateral line. It's a series of pits along the side of the fish. Scientists don't know all of the senses theat this line can detect, but we know it senses vibrations in the water, and may be an important sense for allowing fish to recognize the vibrations of a fish of their own species, allowing them to swim in synchrony in tightly-packed schools.

Pig-tailed macaques: I need information on the pigtailed macaque. I need to know where are its current location in the wild, diet, habitat, locomotion, any sexual dimorphism, group size and ratio of males to females, are there any unusual distinguishing characteristics about their behavior and physical appearance, and what is there status, are they endangered, threatened or safe?

Pigtailed macaques (Macaca nemestrina) are highly sociable animals, and live in large troops lead by a few dominant males. There is a constant struggle for higher status and dominance between the senior males and females, and among the smaller, younger individuals as well. Macaques are ground feeders, inhabiting rainforests in the Malay Penninsula, Borneo, Sumatra and Bangka Island (Indonesia), Burma, Thailand, Yunnan (China), and Laos. They are listed as CITES - Appendix II by the IUCN, which means they are not endangered, but they are "vulnerable to overuse", likely through the pet trade. Individuals who trade this species must acquire a permit.

Coelacanth: My question is about a fish that until the 1950's (I think that's correct) was thought to be extinct. The Cillacanth (may not be spelled correctly) was discovered off a tropical island by local fisherman. What I need is the proper spelling and pronunciation of this fish and as much background as you can give me on the discovery of the not-so-extinct fish.

There is one surviving member of the Coelacanthimorpha, a group of Sacopterygiian fishes that many scientists feel gave rise to the first terrestrial vertebrates during the Devonian Period. They were thought to be extinct since the end of the Cretaceous until one appeared in a deep trolling net hauled up from a fishing boat in 1938 off the coast of South Africa. These creatures live in deep trenches, and no one knows for sure how widespread they are, or how common they are. Many scientists feel that they should be considered endangered, although more information needs to be collected. The species name for this animal is Latimeria chalumnae; the common name, coelacanth, is pronounced (SEEL-uh-kanth).

Animal life spans: Are there any animals with lifespans of 100 years or more? If so, can you tell me a little about them?

Many herpetologists would agree that turtles are among the most long-lived of any animal group. A number of turtle species are thought to be able to live longer than 100 years, including sea turtles, alligator snapping turtles, box turtles, and a variety of large tortoises. Of these turtles, the alligator snapping turtle is probably the longest-lived. At least one has been found with an Indian arrowhead lodged in its shell, suggesting that the animal was alive before Europeans occupied the area. I've heard herpetologists say that they could live at least 300 years, and maybe even 500 years! If you would like more specific information about any of the species I just listed, take a look at the Animal Diversity Web, a web site by the University of Michigan. There, you can do a search by species name.

Dimetrodon and dinosaurs: Would you know if the old name Dimetrodon is still a valid name for the dinosaurs with an extensive dorsal fin? I know that the names for many of the dinosaurs have been changed.

As far as I know, Dimetrodon is still the accepted name. And actually, Dimetrodon lived long before the dinosaurs evolved, about 280-260 million years ago. It was a synapsid mammal-like reptile in a group called the pelycosaurs. Dinosuars evolved much later, about 225 million years ago.