Five Ugly and Bizarre Animals

The vast majority of people loves animals. There has been a plethora of scientific studies that shows that keeping pets is good for our health, not just improving our mental state but also our physical health through reducing stress.

However, whereas there is very little controversy about cute, fluffy kittens or puppies, what about the ugly and bizarre species? Some of them are truly horrid to look at. Others have repulsive habits that can disgust even the most ardent animal lover.

Yet, if you look beneath the skin, so to speak, these animals are truly fascinating. Not just because we are often attracted to the bizarre and repulsive, but because studying how their weird habits adapt them to their ecological niches, can give us fascinating insights into how evolution proceeds.

Below are my favourite five "ugly" animal species.

When I first saw a picture of a mole rat, Heterocephalus glaber, the first thing that occurred to me was that nature was playing a game, trying to design a rodent that would truly horrify people with its ugliness. Naked skin with a few long bristles, check. Tiny, vestigial eyes, check. Long teeth that don't fit in its mouth, check.

True this subterranean rodent from Southeast Africa, will not win any beauty prizes. But if you look beneath the horrible skin, being a naked mole rat has many advantages.

For rodents, these animals have a very long lifespan, they can live to be about 30. In contrast the normal life span of a mouse is 2-4 years. What is even more exciting, is that they seem to be resistant to cancer. This made them very useful subjects for cancer researchers.

Results published this year in the journal Nature suggest that the naked mole rats' cancer resistance comes from their hyaluronic acid (HA) variant. HA is found in all animals, in the space between cells, but naked mole rats seem to have larger HA molecules and more of them. This adaptation gives them loose very flexible skin, which allows the rats to move over each other in the narrow tunnels under the earth.

Other advantages of being a naked mole rat is that they are not bothered by very low oxygen conditions, or high carbon dioxide. The latter fact appears to make them not feel chronic pain, another factor that is being studied by biomedical researchers.

They lack a neurotransmitter, substance P, that is responsible for pain sensation. They feel no pain when treated with acid or chillies.

The social structure of their colonies is also very strange. They are one of only two eusocial mammals known. Their social structure resembles that of ants or termites, there is only one fertile female, the queen, who breeds with a few chosen males. The rest of the colony is made out of workers, and soldiers.

Although called a toad, Pipa pipa is fully aquatic, spending all its time in rivers. It definitely looks bizarre, more like the victim of a bus squashing rather than a frog.

However, it is its reproductive habits that are truly bizarre. Many frogs don't do any kind of parental control, leaving the eggs unattended and the tadpoles to fend for themselves. The surinam toad is one of the exceptions, taking parental care to a fairly extreme extent.

Like with all amphibians the eggs are fertilised externally during amplexus. After this, the eggs roll on the female's back, where they become embedded in the skin. They stay there until they are fully developed toadlets, which then hatch out of their little pockets and swim away.

Surely one of the fundamental characteristics of mammals, is that they give birth to their young, and that females produce milk from their nipples to nourish their young. However the duck billed platypus confounds these expectations.

The duck billed platypus, is classified as a mammal, but it looks like a strange cross between a duck and an otter. It is an amphibious animal that spends a lot of time in the water. It has webbed feet and that bill, rather than a mouth.

The bill is actually soft, unlike that of birds. It is actually a sensory organ with which the animal detects its prey, the mouth is located underneath.

The platypus looks so strange that when it was first discovered by Europeans in New South Wales, and a pelt was send back to the UK in 1798, the British zoologists suspected a hoax, and spent time looking for stitches, since they assumed somebody had sawn different animals together.

The platypus actually lays eggs, like birds and reptiles. It is only one of five species of mammals that does that, the other are four different species of echidna.

The female has mammary glands that produce milk, but it doesn't have nipples. Rather the milk is extruded from pores in the skin and is lapped by the young from the fur on their mother's stomach.

If the flat billed platypus can be considered a primitive mammal, then the hoatzin definitely fills the role of a primitive bird.

It is generally accepted now, that birds evolved from dinosaurs. Some people consider "first bird" to be Archaeopteryx, which had feathers but also a jaw with teeth and claws on the digits of its forelimbs.

Now Archaeopteryx lived in the late jurassic period. However, in the Amazon forests today, you can find the hoatzin, a colourful, chicken sized bird, whose chicks hatch with claws on their thumb and first finger. They use these to help them climb branches before they develop flight capability, although adult birds don't have claws.

The hoatzin also had a unique method of digestion among birds. It mainly eats leaves and relies on bacterial fermentation to digest these, much like cows do. However, unlike cows, this fermentation happens in its crop, which is much larger than other birds. This method produces a strong, manure-like smell, explaining one of the birds' common names, the stink bird.

I am sure most people would agree that lemurs are extremely cute, and would be surprised at including a lemur species in the "exceptionally ugly" list. However, the aye-aye of Madagascar would certainly not win any beauty contests. In fact it is so weird looking that Malagasy people think that it is an evil demon which will bring them bad luck, and kill it whenever they encounter it.

The aye-aye is distinguished by its exceptionally narrow and long middle finger. It occupies the same ecological niche as a woodpecker, feeding on grubs inside trees. It finds tunnels in the tree by tapping its trunk with its finger, and uses its incisors to gnaw a hole. It then captures grubs by fishing them out with its finger.