Category Animal Intelligence

Unique defence mechanisms in animals

Our planet is indeed a wonderland with zillions of creatures inhabiting it, each having its own unique way of adapting to its habitat. Among these, there are some creatures that have developed some bizarre defence mechanisms. Let’s read up on some of these animal species.

IBERIAN RIBBED NEWT

Imagine ribs that you can use as poisonous spikes. The iberian ribbed newt is capable of pushing its ribs outside its skin when attacked. These form spikes which the newt uses to defend itself. The animal does this by moving its ribs away from the spine and increasing their angle by 50 degrees. The tips of the ribs then stick outside the animal’s body, like a set of spines. At the same time, the newt is capable of producing a poisonous milky substance on its body surface. This coupled with its protruding ribs acts as its stinging tool.

GOLDEN POISON FROG

The golden poison frog is one of the most toxic animals on Earth. It is known for its vibrant colours and the potent poison produced by its skin. While its bright colour is itself a warning sign to predators, the frog takes its defence one notch higher by producing toxins such as steroidal alkaloids batrachotoxin, homobatrachotoxin, and batrachotoxin A. These compounds can cause arrhythmias, fibrillation, and cardiac failure in humans.

TEXAS HORNED LIZARD

Here is a lizard that shoots blood from its eyes. When under threat, the Texas horned lizard sprays out pressurised blood from the corners of its eyes at its attacker. In biology, this is called autohaemorrhaging or reflex bleeding. The animal resorts to this when all its other defences such as camouflage fail. This is carried out by the lizard by rupturing its own sinus membranes.

MOTYXIA MILLIPEDE

While the most common defence mechanism is to display vibrant colours to ward off predators, there are some animals that use their bioluminescence as a warning. A genus of millipedes that is endemic to California called the Motyxia uses its bioluminescence to warn off predators. But the most unusual ability this creature possesses is that it can produce and ooze cyanide from the pores on its body. The cyanide is toxic for the predators of this species such as rodents, centipedes, and beetles.

MALAYSIAN ANT

Imagine a defence strategy that kills your predator but you end up getting the raw deal as well. These are the ants that will destroy themselves to defend their colony when under attack. These exploding ants are called the Malaysian ants. Whenever their nest is invaded, they will “blow” up (rupture) their abdomens. The ants have poison glands that get burst when they flex their body, releasing the poisonous substance onto their predator. This can either kill the enemy or incapacitate it.

HAIRY FROG

Meet the “Wolverine” in the wild. When threatened, this frog can crack its own finger bones and pierce them through its skin. These are then used as claws. On one end of the bone, there is a muscle that the frog can use to contract and thereby break a fragment of bone and push it outwards.

Picture Credit : Google 

The secret behind and ant’s gravity-defying grip!

We see them everywhere on the floor, up the ceiling, inside the sugar jar, outside the half-open pouch of a half-eaten snack… Ants are moving constantly, on different surfaces, and make it look so very easy. How do they do it? A biologist studying ants for three decades tells us how.

Ants have six feet, and each foot has five jointed segments. Each of these segments has spines and hairs, which provide the ants traction on rough surfaces such as barks. The last segment also has a pair of claws that help with a good grip on irregular surfaces. Together, both spines and claws act like our shoes – protect ants from hot and sharp objects. But the true magic of how ants conquer almost any surface lies between their claws.

Located between each pair of their claws is an inflatable sticky pad called arolium (plural arolia). When an ant climbs a wall or walks across a ceiling, gravity will pull it. But before that happens, its “leg muscles pump fluids into the pads at the end of its feet, causing them to inflate”. This sticky fluid-called hemolymph- is similar to our blood and circulates throughout its body. A little bit of this liquid oozes out of the arolium when an ant places its leg on the surface, allowing it to stick to the surface. And when it removes its leg from the surface, the leg muscles contract and absorb the liquid back in the body. So, the liquid is used over and over again. Since ants are light-weight, these six pads are adequate enough to give them their gravity-defying grips on any surface “In fact, at home in their underground chambers, ants use their sticky pads to sleep on the ceiling By sleeping on the ceiling, ants avoid the rush hour traffic of other ants on the chamber floors.’’

Did you know?

When we walk, our left and right feet alternate, meaning one foot is on the ground and the other in the air to help us move forward. Ants do the same thing too- when they move, three of their legs are on the surface and three in the air at a time.

Picture Credit : Google 

What are some of the animals that go into hibernation?

Every year, certain animals stay in a comatose state, sending themselves into a sleepy stupor. They hibernate to conserve energy. They cool their bodies by 5° to 10°C and slow down their metabolism. For instance, the Arctic ground squirrels cool themselves to subfreezing temperatures! They do wake up and warm up intermittently. Some animals even hibernate as a response to the shortage of food. Here we take a look at some of the animals that go into hibernation.

SNAKES

In the case of snakes, they experience brumation, where they remain dormant. is technically different from hibernation, but they prepare for the winter by going into a state of partial sleep. This helps them conserve energy for breeding. The length of the dormancy varies according to the location of the snakes. While some may go into brumation for weeks, others might for months. There are also occasions when they venture out of their resting spot for hydration. While some snakes brumate alone, some such as the garter snakes brumate together, more like a communal brumation.

BEARS

Think hibernation and the first animal that comes to your mind is the bear. Of course, when the winter sets in, they go into hibernation and survive the winter thus. But with climate change and changes in the temperature, bears have been seen to come out of their hibernation a bit earlier than usual. According to wildlife experts, this early emergence from hibernation isn’t good for the animal.

COMMON POORWILLL

You wouldn’t have heard about birds going into hibernation. Yet there is one bird that does the unthinkable. The Common poorwill is the only bind that hibernates, the sole reason being that the bird’s insect food isn’t available during the winter season! So instead of migrating, like other birds do, they pull through the winter by huddling inside a hollow log, lowering their metabolism and hibernating.

MARMOTS

With the onset of fall, marmots use dirt and plants to cover their tunnel entrances. They are preparing for the annual ritual of hibernation to hide from predators. For about 8 months of a year, the marmots go into hibernation. During this inactive state, they burn the fat that they stored and slow down their vitals. They even reduce their heart rate. And once spring sets in, they emerge from the hibernation.

SNAILS

Did you know that snails also hibernate? Well, some snails hibernate during the colder months. They cover their bodies in a layer of mucus. They crawl into their shell and seal the entrance with mucus. This thin mucus layer prevents them from drying out. The same  activity is carried out by some snails during the summer and this is called aestivation, a prolonged period of inactivity to survive the dry periods.

BUMBLEBEES

While not all bees go into hibernation, bumblebees do. In fact, they hibernate for a longer period of their lives. Some queen bees even hibernate for nine months. That is like three-fourths of their entire life span!

Picture Credit : Google 

What role do ants play in the ecosystem?

Just like other insects and invertebrates, ants are a crucial part of nature. The large role played by these tiny creatures in keeping an ecosystem going is the kind of stuff wonders are made of.

A recent research published conservatively estimates that our planet harbours about 20 quadrillion ants – that’s 20 thousand million millions, or in numerical form, 20,000,000,000,000,000 (20 with 15 zeroes!). It is further estimated that the world’s ants collectively constitute about 12 million tonnes of dry carbon. This exceeds the mass of all the world’s wild birds and wild mammals combined. It’s also equal to about one-fifth of the total weight of humans.

Counting the world’s ants

The astounding ubiquity of ants has prompted many naturalists to contemplate their exact number on Earth. But these were basically educated guesses. Systematic, evidence-based estimates have been lacking.

The latest research involved an analysis of 489 studies of ant populations conducted by ant scientists from around the world. This included non-English literature, in languages such as Spanish, French. German, Russian, Mandarin, and Portuguese.

The research spanned all continents and major habitats, including forests, deserts, grasslands, and cities. They used standardised methods for collecting and counting ants such as pitfall traps and leaf litter samples. As you can imagine, this is often tedious work.

The previous figures employed a top-down” approach by assuming ants comprise about 1 % of the world’s estimated insect population. In contrast, the “bottom-up” estimate in the recent research is said to be more reliable because it uses data on ants observed directly in the field and makes fewer assumptions.

The next step was to work out how much all these ants weigh. The mass of organisms is typically measured in terms of their carbon makeup. It was estimated that 20 quadrillion average-sized ants corresponds to a dry weight or “biomass” of approximately 12 million tonnes of carbon. This is more than the combined biomass of wild birds and mammals – and about 20% of total human biomass. Carbon makes up about half the dry weight of an ant. If the weight of other bodily elements was included, the total mass of the world’s ants would be higher still.

A few caveats, but…

The findings come with a few caveats. For example, the sampling locations in the dataset are unevenly distributed across geographic regions. And the vast majority of samples were collected from the ground layer, meaning they have very little information about ant numbers in trees or underground. So, the findings are somewhat incomplete.

But what is clear is while global insect numbers are declining due to threats such as habitat destruction and fragmentation, chemical use, invasive species and climate change, data on insect biodiversity is alarmingly scarce. It is hoped that the recent study provides a baseline for further research to help fill this gap because it is in humanity’s interest to monitor ant populations. Counting ants is not difficult, and citizen scientists from all over the world could help investigate how these important animals are faring at a time of great environmental change.

WE ALL NEED ANTS

  • Ants provide vital “ecosystem services” for humans. For instance, a recent study found ants can be more effective than pesticides at helping farmers produce food.
  • Ants have also developed tight interactions with other organisms – and some species cannot survive without them. For example, some birds rely on ants to flush out their prey. And thousands of plant species either feed or house ants in exchange for protection, or dispersal of their seeds.
  • Many ants are predators, helping to keep populations of other insects in check.

DID YOU KNOW?

  • Eminent biologist Edward O Wilson once said insects and other invertebrates are the little things that run the world- and he was right Ants, in particular, are a crucial part of nature.
  • Among other roles, ants aerate the soil, disperse seeds, break down organic material, create habitat for other animals, and form an important part of the food chain.
  • Estimating ant numbers and mass provides an important baseline from which to monitor ant populations amid worrying environmental changes.
  • There are more than 15,700 named species and subspecies of ants, and many others not yet named by science. Ants high degree of social organisation has enabled them to colonise nearly all ecosystems and regions around the globe.
  • Ants are distributed unevenly on Earth’s surface. They vary sixfold between habitats and generally peak in the tropics. This underscores the importance of tropical regions in maintaining healthy ant populations.
  • Ants are also particularly abundant in forests, and surprisingly, in arid regions. But they become less common in human-made habitats.

Picture Credit : Google 

DINOSAUR DADS TOOK CARE OF NEST

Among bird-like dinosaurs such as the Troodon, Oviraptor and the Citipati, it was the male which guarded the nest and brood. This came to light when scientists who studied the fossil remains of these dinos found the males with large clutches of eggs.

For the new research, paleontologist David Varricchio of Montana State University in Bozeman compared three species of birdlike dinosaurs–Oviraptor, Citipati, and Troodon–with birds and crocodiles. All three types of dinosaurs were found on nests, and those nests contain large clutches of eggs, as many as 30 each. Varricchio and his colleagues investigated whether they could discern the nesting behavior from the relationship of the clutch size and the animal’s body size. Measurements in 433 living birds and crocodiles revealed that, for a given body size, species in which males took care of the nest tended to have the largest clutches. The next-largest clutches were cared for by mothers. Mom-dad partnerships had the smallest clutches. Extrapolated to dinosaurs, the data revealed a pattern of paternal care in the ancient beasts.

Another line of evidence in the paper comes from Gregory Erickson, a biologist at Florida State University in Tallahassee. His studies of dinosaur bone tissue showed that none of the seven specimens associated with nests showed signs of changes associated with egg laying, such as medullary tissue . That’s not sure-fire proof the nest-caretakers were male, he notes, but it’s consistent with the hypothesis. The findings are reported in tomorrow’s issue of Science.

Richard Prum, an ornithologist at Yale University, says he never expected paternal care in dinosaurs. But with their dinosaur ancestors showing more and more traits once thought to be exclusive to birds, such as feathers, he says the finding makes sense. It also points to a question on the reproductive frontier: Did dinosaurs practice polygamy?

Picture Credit : Google

Why are koalas special?

Did you know that koalas smell like cough drops? This is because they eat a diet that mainly consists of eucalyptus leaves. Most people believe that the koala is a bear, but it is actually a marsupial like the kangaroo. Baby koalas are carried in their mother’s pouch till they are about 6 months and then on her back for another 6 months till they are weaned.

Koalas may seem slow because they are always sleeping! These adorable tree huggers doze for 18 to 20 hours a day! This is not because the koala is lazy, but because the eucalyptus leaves that it eats do not provide much nutrition and the koala has learned to conserve its energy. However, a disturbed koala can break into a bounding gallop, moving at a speed of up to 30 km/h.

Koalas are native to Australia and spend most of their time up in the trees. The word koala means ‘no drink’ in the Aboriginal language, as koalas manage to get their daily supply of water from the leaves that they eat. However they are known to occasionally drink from creeks and streams.

Koalas are nocturnal and have poor vision. They rely heavily on other senses like hearing, which helps them to detect the presence of predators and other koalas. An adult koala is about 24 inches long and weighs about 14 kg.

Koala populations in Australia have shown a decline in the past years due to climate change, habitat loss, bushfires and diseases. As of February 2022, Australia has upgraded the conservation status of koalas from ‘vulnerable’ to ‘endangered’. It is feared that the koala will be extinct by 2050, unless world-wide efforts are made to reverse climate change.

Picture Credit : Google