My Science School

In the animal kingdom, you will see that there are animals and insects with scales or shells. These help the animals protect themselves from predators. Animals both on land as well as in sea can have scales or shells. Let us take a look at some such animals.

GILA MONSTER

The Gila monster is a tough, heavily bodied lizard whose body is covered with beadlike scales called osteoderms. The scales cover all of its body except the belly. The lizard is known for its strong and venomous bite. When it bites its prey, the lizard doesn't loosen its grip for several seconds and this allows the venom to flow into its prey. These lizards live in desert and semi-desert areas and are large-bodied, with short, fat tails.

PANGOLIN

Solitary, nocturnal creatures, pangolins are known for their body covered in an armour of scales. These scales help in protection. When threatened, the pangolin will use its front legs to cover its head and expose its scales. It can roll itself into a ball when it is touched. Pangolins are called scaly anteaters because of their diet which includes ants, termites, and larvae. They have no teeth and use their tongues to gather food. They live on the ground while some can climb trees. As many as eight species are found, with a distribution of four species each in Asia and Africa.

SEA URCHINS

 Sea urchins are spiny marine invertebrate animals. These sea animals live in tidal areas and the deep ocean and are seen on the seafloor. They are noted for their round-shaped spiked shell called "test". They move across the ocean floor using their tube feet, which are small anatomical features seen on their undersides. The spines stretch out of the test and are used to move when they come across obstacles such as rocks. The largest urchin is the Sperostoma giganteum and is seen in Japan. As many as 950 species of sea urchins exist.

ARMADILLO

Armadillo is Spanish for "little armoured one". The name refers to the bony, armour-like plates that the animal has. The set of plates covering the animal's body is called the carapace. An animal found in the tropical and subtropical regions of Central and South America, the armadillo lives in open areas such as grasslands while some live in forests. In all, over 20 species of armadillo exist. Did you know that two species of armadillo are able to roll up completely into a ball? The animal uses this technique to protect itself.

DIABOLICAL IRONCLAD BEETLES

With an extremely tough outer shell that justifies their name, the diabolical ironclad beetles are considered to withstand a lot of pressure and are almost unbreakable. The outer wing case of these beetles are called elytra. They inhabit the woodlands of western North America. They live under tree bark and cannot fly. Their elytra is fused together tightly and from a shield. When compression tests were carried out by scientists to test how much force the shield could withstand without cracking, it was found that force up to 149 newtons could be withstood by their shields.

LONGHORN COWFISH

The Longhorn cowfish is known for its uniquely shaped body. Its cubical body is encased in a protective hard shell called carapace and is made up of hard, bony plates. It is a solitary species and is found among seagrasses, reefs, harbours, estuaries, and so on. Its tiny fins and tail jut out from its shell. It received its name from the pair of horns that project from its eyes.

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Invasive species are those that get introduced to a new ecosystem, where they end up replacing or affecting the native fauna or flora. These are mostly introduced by humans. Let's read up on a few of the invasive species.

WILD PIGS

The wild pigs are native to Eurasia and parts of North Africa. Also called wild boar or feral hogs, the wild pigs arrived in the 1500s in the U.S. and are one of the most invasive species in North America. They were shipped in by Spanish colonisers as a mobile meat source. Over time, they populated the forests of the southeastern U.S., where their genes got mixed with escaped domestic pigs. They are such a threat as they can live anywhere, eat anything, and have a very high reproductive rate. They destroy crops, landscapes and spread diseases.

MOUNTAIN PINE BEETLE     

A small bark insect, the mountain pine beetle depends on a host tree to feed and lay its eggs. They may seem inconspicuous, with just about one-fourth of an inch in length but they are one of the worst invasive species. They have had a massive impact on the pine forests, boring holes in the tree's bark. They lay eggs in these holes under the bark and deposit a fungus that eventually kills the tree. In fact, in 1995, an outbreak of this pest in the western United States and Canada led to the destruction of millions of acres pine forest.

BURMESE PYTHON

The Burmese python is one of the most concerning invasive species in South Florida where they have established a breeding population. They have even replaced alligators as the apex predator in Florida and have led to the decline of many native species, with the population of small animals dropping at alarming rates. Populations of raccoons, opossums, bobcats, marsh rabbits, cottontail rabbits, and foxes have all been on an alarming decline. These pythons got introduced as a result of the exotic pet trade after they escaped from their owners or got intentionally released into the wild by their owners.

BROWN TREE SNAKE

The brown tree snake was introduced to the Pacific island of Guam in the 1950s. And ever since its introduction, it led to the decimation of the native bird and animal populations on the island. It is believed to have been introduced via cargo ships or aircraft. The snakes which easily spread across the island also cause power outages when they climb electrical wires! Among the 11 native bird species in Guam, nine species went extinct after the snake's introduction.

EUROPEAN STARLING

European starlings are an invasive species in the United States. Interestingly enough, its arrival was the result of a plan to introduce all the species referred to in the works of English playwright William Shakespeare. These birds are native to Europe, Asia and northern Africa but easily took to the landscape of the U.S. and spread quickly across the country, affecting the population of native bird species.

LANTANA CAMARA

One of the worst invasive species in the world, Lantana camara was introduced in India by the British in the 1800s. It came in as an ornamental plant but ended up taking over several ecosystems as an invasive plant. Its ability to spread on the forest floor, climb over trees as a creeper or entangle with other native plants aided it in establishing itself. It continues to spread in India even as methodologies are being adopted to weed it out.

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When the COVID-19 pandemic hit us way back in 2020, several regions across the world went into lockdown. Around the same time, several stories of wildlife sightings at unusual places surfaced. A group of animal movement researchers tells us more about what could have caused this.

At some point in 2020, more than half the world's population was said to have been under lockdown. With hardly any human movement, many bustling places became quiet. That was when "cougars were seen prowling through the suburbs of Santiago, Chile, golden jackals became more active during the day in Tel Aviv, Israel, and dolphins appeared in the normally busy harbour of Trieste, Italy". This made animal movement researchers wonder if human movement impacted animal movement or if humans were simply noticing animal presence better during the pandemic. And so, they commenced the COVID-19 Bio-Logging Initiative. Many of the researchers were already studying animals and recording their movements through GPS tags, etc. The devices continued their work during the lockdown too, helping them compare animal movement during and before the pandemic.

Their data showed movements for thousands of animals, "from 43 species including elephants, giraffes, bears, deer and cougars". The researchers could "look at how their behaviour and movement patterns changed during the lockdowns in 2020 compared to the same period one year earlier”. Both humans and the structures (including buildings and vehicles) they build can impact animal mobility, and the study showed this- "mammals were 36 per cent closer to roads during lockdown, and that their movement distances over ten days were 73 per cent longer during strict lockdowns compared to the same period one year earlier”. The researchers feel that less traffic could have helped mammals get closer to roads while absence of humans could have prompted them to explore new areas.

But not all species demonstrated this change, indicating difference in lockdown policies among countries and "differences between species in their ability to change behavior”. It is likely that "some species are more flexible in how they respond to changes in human activities".

The findings of the study point to how humans impact animal behaviour. "With this knowledge we can start to think of new ways to change our behaviour that will positively impact wildlife."

Picture Credit : Google