Maria Ny’s Ask Auntie Antelope Blog

According to the Penguin Dictionary of Biology (Abercrombie et al., 1966), Amphibia are a class of vertebrates represented by three orders: Anura (Frogs and Toads), Urodela (Newts and Salamanders) and Apoda (strange burrowing worm-like creatures called Caecelians, pronounced seh-SILL-yuns).

The word Amphibian is derived from the greek words amphi, which means “two” and “bios” means lives. This refers to the fact that they spend part of their lives under water (breathing with gills) and the remainder on land (breathing with lungs). There are about 5,500 known species of amphibians.

Amphibians are cold-blooded (ectothermic), meaning that they cannot internally regulate their body heat like mammals. They rely completely on warmth from the sunlight for warmth and a burrow, other form of shade or water to cool down. Amphibians don’t drink. Instead, they absorb water and much of the oxygen they need through their skin.

Aquatic amphibians lay their eggs in a big mass, outside the body. Fertilization occurs by the male squirting his sperm over these eggs (external fertilization). Amphibians that reproduce this way need water or moist soil for breeding. Without water, their eggs (which are not protected by a shell) would quickly dry out and the young would die before they even had a chance to develop. But, there are also many species of amphibians that fertilize their eggs internally and many that do not require water fertilization.

There are people who think that amphibians all undergo metamorphosis and that they all hatch and start off as tadpoles. This is true with the aquatic amphibians, but there are a lot of species that do not undergo the free-swimming tadpole stage. Rather, they undergo direct development in burrows to adulthood.

Some amphibians avoid the drying effects of the sun by being active only at night (nocturnal). Others shelter in moist habitats under logs, rocks, leaves, mosses and ferns.

Characteristics of Amphibians:

1. Circulatory system has a 3 chambered heart with a separate blood circuit through the lungs.
2. Skin must remain moist. It is highly vascularized because it acts as a respiratory surface (sometimes the only respiratory surface).
3. Some amphibians, the caecelians, have internal fertilization. Most amphibians deposit eggs in water where they are externally fertilized.
4. All amphibians are at least in part, dependent on environmental water.

Amphibian or Reptile?
If you see an animal and you can’t tell whether it’s an amphibian or reptile, examine the skin. If it’s hard and scaly with scutes or bony plates, it’s a reptile. An amphibian’s skin is soft and smooth or warty-looking, and it may also be moist.

What kind of amphibian is it?
If it has legs and a tail, it’s a salamander or newt. If it doesn’t have a tail but has legs, it’s a frog or toad. And it’s easy to tell Caecelians from other types of amphibians because they look like worms.

The largest amphibian is the Japanese giant salamander (Andrias japonicus), at 6 feet long (1.8 meters) and 140 pounds (63 kilograms), and the smallest is an Izecksohn’s toad (Brachycephalus didactylus) that weighs just a few grams.

Around a third of amphibian species are threatened with extinction. Traditional threats to species and ecosystems (such as habitat loss and pollution) are being compounded by new threats such as climate change and emerging disease.

There actually are no scientific distinctions between frogs and toads. The term “frog” is actually a general term for any amphibian grouped under the superorder Salienta and order Anura, which includes all species of frogs and toads. The name Anura comes from the Greek an (without) and ura (a tail), referring to their tailless condition. Twenty-five families with over 4,000 Anuran species are currently recognized today, with more being discovered regularly.

Characteristics all frogs and toads share in common include the fact that all frogs and toads:

• Are amphibians, meaning double life because many species of both spend part of their time in aquatic (water) and terrestrial (land) environments. Amphibians are cold-blooded vertebrate animals. Unlike reptiles, amphibians have no scales.
• Hatch from eggs as tadpoles and experience the process of metamorphosis, meaning a change (meta) in form (morpho). At birth, the tadpoles will generally attach themselves to wees or grass in the water. In 7 to 10 days, they start swimming around and feeding on algae. They start absorbing their tails and growing legs after about 6 to 9 weeks. About 12 weeks of age, tadpoles become froglets and only have tiny stubby tails. Between 12 and 16 weeks, froglets completely absorb their tails and leave the water, becoming adult frogs.
• Can breathe through their skins.
• Lay eggs in water or in moist terrestrial sites.
• Rest with their eyes closed and hibernate in the winter.

However, while all toads are frogs, not all frogs are toads. True frogs (members of the family Ranidae, containing more than 400 species) are not considered toads. And, even though there are several families of toad, the common name “toad” is given specifically to members of the family Bufonidae (true toads), which contains more than 300 species. Here are some of the differences between true frogs and true toads:

• True frogs can be found on every continent except Antarctica. True toads can be found worldwide except in Australasia (a region of Oceania that includes Australia, New Zealand, and neighbouring islands in the Pacific Ocean), polar regions, Madagascar, and Polynesia. However, the giant toad (Bufo marinus), also known as the cane toad and marine toad, has been artificially introduced into Australia and some South Pacific islands.
• True frogs have two bulging eyes and long, strong legs for hopping. They also have fully-webbed hind feet that are adapted for swimming. True toads have fat boddies with short legs that are mainly used for walking instead of hopping. They have almost no webbing on their hind feet.
• True frogs generally spend most of their lives in or near water, so they have smooth, clammy skin. True toads are typically land-dwellers that find their way into gardens and yards. They have dry, bumpy skin.
• True frogs are usually brightly colored. True toads, on the other hand, are generally well-camouflaged to blend in with their environments.
• True frogs are active hunters, leaping out to pull in their prey. True toads are ambush hunters that wait for their prey to pass before attacking.
• True toads have paratoid (poison) glands behind the eyes. They exude a white fluid through these glands and through their skin that is very poisonous. It causes intense burning if it comes in contact with the eyes or mouth.
• True toads have a special organ that true frogs don’t have–the Bidder’s organ, which is a vestigial ovary that is found in the male toad.
• True frogs have upper and lower teeth. True toads don’t have upper teeth.
• True frogs generally lay their eggs in clusters, while most true toads lay theirs in long chains, with the exception of genera Nectophrynoides–the only anurans that bear live young.
• A true frog’s back is raised with two ridges down each side. True toads have a more flattened appearance.
• The true toad’s chest cartilage is different than that of the true frog’s.
• A group of frogs is called an “army”, while a group of toads is called a “knot”.

Yes, it can. Rattles are delicate and can be lost to predators. They can also get caught somewhere or be lost by other means.

There are over 500 species of venomous snakes, distributed worldwide grouped into two main categories: rear-fanged and front-fanged.

Both types have hollow fangs with a cavity running down most of its length. These fangs work like hypodermic needles. Venom from the venom gland enters the snake’s fangs through the venom duct and travels down the hollow canal in the snake’s fangs when the snake opens its mouth. The venom is then injected into the victim through its incredibly sharp, pointed fang tip orifices (openings) when the snake bites down. When biting, a front-fanged snake merely strikes, ejecting the veonom the moment the fangs penetrate the skin, then immediately letting go. While the rear-fanged species actually close their jaws like a dog and hold the prey firmly for a considerable amount of time.

Some species of cobra, commonly called “spitting cobras”, can actually shoot venom from their mouths accurately at a distance of about 4 to 8 feet. Another species of snake, the Rinkhals Cobra, can also spit venom. It is not actually a cobra, but is closely related to them.

Spitting snakes have modified fangs. Inside the fangs are channels which make a 90-degree bend in the lower front of each fang. When these snakes are threatened, the muscles of the venom gland squeeze the venom sack, projecting the venom forward while air expelled from the snake’s lung blows or sprays the venom at its intended victim with the velocity equivalent to that of a water pistol.

Spitting snakes can spit 30 to 40 times in succession and still deliver a lethal bite. Spitting is only used for self-defense against larger animals and humans, not for killing its prey. The snake aims for the eyes of a perceived threat where a direct hit can cause temporary shock and blindness by severely inflaming the cornea and conjunctiva. If left untreated, the blindness could become permanent. To treat, flush the eyes out with plenty of milk. If milk is not available, water will work. In an emergency, urine is an acceptable treatment. Venom on the skin isn’t dangerous, but open wounds could possibly become envenomated.

The size of the snake’s venom gland, venom toxicity, size of the fangs and the size of the fang openings determine how toxic the venom is. Most rear-fanged snakes deliver small amounts of venom slowly and therefore are not a major health threat to humans because their fangs and fang openings are small, and they generally have small venom glands. However, there are notable exceptions, such as the African boomslang which has been responsible for human fatalities. Front-fanged snakes are the most common and recognizable venomous snakes. These snakes are responsible for human fatalities world-wide because their fangs and fang openings are larger and their venom glands are generally larger, as well.

The gila monster is one of two poisonous lizards in the world. The other is the Mexican beaded lizard. The gila monster, like the Mexican beaded lizard, inject venom into its prey by biting down and squirting the venom down through gooves in its teeth.

“Firefly” is the common name for the nocturnal luminous insects belonging to the beetle family Lampyridae (order Coleoptera). They are also known as lightning bugs. These names come from the fact that some species as adults emit flashes of light to attract mates in order to reproduce, using special light-emitting, photic organs in the abdomen.

The photic organs produce light by means of a chemical reaction consisting of Luciferin (a substrate) combined with Luciferase (an enzyme), ATP (adenosine triphosphate) and oxygen, producing a “cold light” because there is almost no heat in the glow. When these components are added, light is produced. All known firefly larvae (also known as glowworms) produce light, but many species of fireflies do not glow as adults.

At night, the last abdominal segment of the firefly glows a bright yellow-green color. The firefly can control this glowing effect. The brightness of a single firefly is 1/40 of a candle, which is why the ancient Chinese sometimes captured fireflies in transparent or semi-transparent containers and used them as (short-term) lanterns. Fireflies use their glow to attract other fireflies. Males flash about every five seconds; females flash about every two seconds.

The rattle is made up of nested, hollow beads of dry, hard pieces of modified scales from the tail tip. A new rattle segment is added each time the snake sheds. The vibration of these shell-like rings on the end of its tail is what makes the rattling sound.

Some people think that you can tell the age of a rattlesnake by how many beads there are on its rattle–they think that snakes only shed once a year. But, this isn’t true. Rattlesnakes shed as they grow, and even as adults shed more than once a year. Plus, rattlesnakes sometimes lose their rattles to predators or by other means. So, the rattle is not an accurate way to determine a rattlesnake’s age. However, the number of rings can sometimes determine how big the snake is. Baby rattlesnakes are born without rattles. They don’t form the first segment of their rattle until one to two weeks of age when they shed their skin for the first time. As the snake grows, the number of segments increases. So the louder the rattle, the bigger the snake unless the snake has lost segments of its rattle or lost the rattle altogether.

Snake venom is a highly-mofified saliva produced by specialized glands, called “venom glands.” Venom consists of complex mixtures of many toxins and enzymes which effectively immobilize prey and assist in digestion. All snake venoms have one or more of the following components: hemotoxins (including hemorrhagins and hemolysins), myotoxins, and neurotoxins. Enzymes in snake venom include Amino acide oxidases and proteases, Hyaluronidase, Phosphodiesterase and ATPases.

• Hemotoxins primarily attacks the blood by destroying red blood cells and preventing coagulation while at the same time aggressively destroying its victim’s blood vessels.
• Myotoxins lead to severe muscle necrosis (death of cells and living tissue in the muscles). Myotoxins act very quickly, causing instantenous paralysis, to prevent prey from escaping, and eventual death due to diaphragmactic paralysis (paralysis of the diaphragm)–the diaphragm is crucial for drawing air into the lungs.
• Neurotoxins attacks the nervous system, causing massive respiratory malfunctions, heart failure and even paralysis. These symptoms are also normally accompanied by blurred vision, dry mouth, a metal taste and dizziness.
• Phosphodiesterases are used to interfere with the prey’s cardiac system, mainly to lower the blood pressure.
• Hyaluronidase increases tissue permeability which increases the rate that venom is absorbed into the prey’s tissues.
• Amino acid oxidases and proteases help the snake digest its prey. It also causes the venom of some species to be yellow.
• ATPases are used for breaking down ATP (Adenosine triphosphate) to disrupt the prey’s energy fuel use.

Coprophagia is defined as the consumption of poop. Little research has been done on this particular behavior, so veterinarians can only guess why dogs do this. However, dogs aren’t the only animals that eat poop. Many other animals eat poop on a regular basis including rodents, gorillas, many insects such as dung beetles and flies.

Herbivores such as rabbits and rodents eat their own poop because their diet of plants is hard to digest efficiently, and they have to make two passes at it to get everything out of the meal. This is equivalent to a cow chewing its cud. However, because a cow has four stomachs, they are able to re-eat their food without having to poop it out first. Deer, moose and other four-stomached herbivores also chew their cud.

Many animals, including dogs, eat poop because poop contains vitamins produced by the intestinal bacteria that the animal can’t absorb through the intestinal wall. So, they get these vitamins by eating poop. Another reason that some animals, including dogs, eat poop is because poop contains protein. Dogs are particularly fond of cat poop because cat poop is high in protein.

Sometimes dogs may eat poop out of boredom; others may observe other dogs eating it and imitate the behavior. It may be a way of getting attention because owner tends to reprimand them and, therefore, pay attention to the animal. A female dog will eat the poop of her pups as a way to keep the den clean and reventing the scent of the poop from attracting predators. Some particularly dominant dogs may eat other dogs’ poop order to remove it, and therefore remove other dogs’ presence. This is because poop is one way in which dogs mark territory.

Some scientists believe that eating poop is just a trait passed down to dogs from their ancestors. Coyotes and wolves have been known to eat their own poop during food shortages, and have also been known to eat the poop of herbivores which contain many of the B vitamins. Starving dogs will eat their own poop, as well.

It may even be possible that there is no theory or particular reason why dogs eat poop. They may do it simply because it tastes good to them. Whatever reason they do it, try to keep them from eating poop because many parasites, including giardia, coccidia, roundworms and whipworms, can be transmitted through dog and cat poop. Additionally, clumping litter can pose a health threat to dogs if they eat it. Think of what the litter does when a cat urinates in it. Similar things may happen in a dog’s stomach if it eats enough of the litter.