Animal Life

What animal has the longest gestation period?

You might think the animal with the longest gestation period would be one of the larger mammals, but in fact it is the Alpine black salamander. It is a viviparous amphibian which lives in the high altitude Swiss Alps. At altitudes above 4,600 feet, it’s gestation period can be up to 38 months. It bears two fully metamorphosed young.

How can you tell the age of a fish?

Like the rings on the cross section of a tree, fish scales also have rings. Fish scales have concentric ridges called circuli which reflect the growth patterns of the fist and can be used to estimate the age. From “The Handy Science Answer Book,” the portion of the scale that is embedded in the skin contains clusters of these circuli, called annuli. Each of these clusters mark one year of growth.

So what about fish that don’t have scales? Like catfish, dolphins or sharks? I’ve heard that a seasoned biologist (or ichthyologist) could possibly make a fair estimate by looking at their teeth. But I would take this answer with some skepticism and say that this is probably difficult to do.

What is the slowest animal in the world?

Source: http://mindjourney1962.wordpress.com

There are a couple of ways this question can be answered. Sea anemones and sponges are animals and they hardly move at all, so I guess one of these guys could be considered very slow indeed. Clams, oysters and snails are pretty slow as well. But I guess most people asking this question are actually wondering what are the slowest vertebrates.

The winner in this category is most likely the three-toed sloth. It has been said that it would take a sloth about a month to walk a mile, though this is still a bit unfair since sloths really don’t ever walk. They spend their time hanging upside down in trees. They even sleep, eat and have babies while hanging upside down. I imagine they even do what they do to make babies while hanging upside down, but I’ve never personally witnessed sloth copulation. Probably a good thing.

What is the most poisonous snake in the world?

While this question is often debated, the land snake commonly believed to have the most lethal poison in the world is the inland taipan. They primarily live in the arid deserts of central eastern Australia. Anything or anyone unlucky enough to be bitten by a taipan is injected with some nasty venom

Inland taipans are also called fierce snakes and can grow up to 10 feet (2.7 meters) although half of that is the norm. This snake changes color according to season. They range from dark brown to straw colored during the year but at winter they go darker and in the summer they go lighter.

Taipans hunt mammals so their poison can knock out warm-blooded, fuzzy rodents and animals, including humans. In a single strike (one bite) the venom can quickly paralyze a small animal or wipe out several adult humans. As the poison spreads, the victim will encounter headaches, nausea, vomiting and stomach pains. Sometimes there are convulsions and in extreme cases, coma.

If that’s not bad enough, the poison eats away at muscle tissue. Urine from the victim turns reddish-brown as their muscles deteriorate and pass through the kidneys. Internal bleeding is a major problem from taipan bites. The poison also prevents blood from clotting so the bite continues to bleed. This can cause internal hemorrhaging, especially in the brain. All this sucks for the bite victim but it’s great for the snake who only has to wait for its prey to stop convulsing before enjoying dinner. Taipans rarely attack humans, except in self-defense, so as long as they are left alone, humans will be too.

Source: Kidzworld.com.

How Can I Tell What Kind of Tadpoles I Have?

This is a tricky question and one that has befuddled many biologists for a long time. The easiest way, but not always 100% accurate, would be to find a frog near where you found the tadpoles and there’s a good chance they are the same species. If you can’t find an adult frog, do a little research on the amphibious wildlife indigenous to your area and you may be able to narrow it down a bit more. This won’t always give you a firm answer, as many areas will have several native species of frogs.

A more scientific method is through close observation and comparing your tadpole to a known chart. The below images and chart should help you get started.

First, where are the eyes? Are they lateral or dorsal?

Next, check the vent location. You may have to hold the tadpole Read more…

Do dogs only see in black and white?

Not entirely. It is generally agreed that dogs can distinguish fewer colors than humans, but their vision isn’t entirely restricted to black and white. Rods and cones are the two types of receptors in the retina that most of us have heard of. The rods are more light sensitive and help for seeing in low light conditions. The cones help with focusing on more detailed objects and are what help distinguish between colors.

A dog’s retina has a much higher proportion of rods than cones than the human retina. This is why we can see more details at a longer distance than our dogs, but they can see better than we can in low light conditions. One estimate is that a dog can see at about 25 yards what we can see at 75 yards. If this is the case, we could call a dog’s vision 20/75 on the standard 20/20 scale. Of course these are estimates as it would be pretty difficult to get a dog to read an eye chart at any distance.

So why did the dog’s and man’s retinas evolve this way? Most likely because it was more advantageous for the dog to be able to see in low light conditions. The nearest wild relative to the dog is the wolf, which often hunts near the hours around dawn and dusk. Many predators hunker down during the middle of the day and thus don’t need to have the best vision in this time. Man evolved from any nocturnal habits such as these millions of years ago and has likewise benefited from having better daytime vision- ie., we have evolved to have more cones than rods.

Source: Wikipedia’s entry on dogs, eyesight.

Is a dog’s mouth really cleaner than a human’s?

The short answer is no. While this myth seems to have been around a while, it has been debunked by several reputable articles over the years. According to ABC News, the mouth of a typical dog is full of bacteria but it is “species specific” so the bacteria inside a dog’s mouth may be completely harmless to us. Read more…