My Science School

Several species of agricultural crops depend on bats for pollination. In addition, fruits bats help in the dispersion of seeds, keeping several species of fruit-bearing trees alive. Some species of bats consume insects, considered agricultural pests. This not only prevents the use of billions of dollars worth of pesticides annually but also allows the soil to remain free from harmful chemicals.

The fungus Pseudogymnoascus destructans causes white-nose syndrome in bats, and "is responsible for the deaths of over six million bats in North America". This is one of the reasons for the decline in the population of bats globally. And, scientists say that this decline is of concern. What causes the plunge in their numbers, and why should we be worried? Come, let's find out. Often labelled blood suckers and disease carriers, bats seem to get short shrift. Pop culture portayals of vampires and the endless speculation over the origins (often pointing to bats, albeit scientifically unproven) of the ongoing pandemic make it even worse for the world's only flying mammals. Add to the fact that these nocturnal creatures usually do their work under the cover of darkness, their role in healthy ecosystems may not be appreciated by laypeople. Several species of agricultural crops such as banana, mangoes, avocadoes, and figs are said to depend on bats for pollination. In addition, fruit bats help in the dispersion of seeds, keeping several species of fruit-bearing trees alive. Some species of bats consume insects, considered agricultural pests. This not only prevents the use of billions of dollars worth of pesticides annually but also allows the soil to remain free from harmful chemicals. In fact, guano - the excrement of bats - makes for excellent manure. Found in all continents except Antarctica, bats are a part of different types of ecosystems - from rainforests to deserts. Irrespective of the region they inhabit, they play crucial ecological roles, keeping alive the biodiversity and the health of their ecosystems.

While the population of bats in North America has taken a huge hit due to the white-nose syndrome, there's a general decline in their population in other parts of the world too. The reasons for this include climate change, invasive species, loss of habitat due to urbanisation and agriculture, lack of food, especially when pesticide is used to kill the insects they feed on, etc. There's still a lot to be studied about bats. But an aspect of concem in studying bats is that they "roost in lots of different places, from caves to barns to attics, and scientists can't monitor bats in all places at all times".

Picture Credit : Google 

Blue whales are the biggest animals that have ever inhabited our planet. These marine mammals grow up to 22 metres in length and to a weight of 150,000 kilograms. Their tongues alone weigh as much as an elephant in some cases and their hearts can be as big as an automobile.

The most interesting detail about these huge creatures is the fact that they reach these immense body sizes by consuming tiny shrimp-like animals called krills alone. In some seasons, a single adult blue whale eats about 4000 kilograms of krill a day.

Blue whales belong to the family of baleen whales. Baleen is a fringed plate made of fingernail-like material that is attached to their upper jaws. These giant animals feed by first gulping a great amount of water through their mouth and then they expand the pleated skin on their throat and belly to take it in. After this, the whales use their massive tongue and force the water out through the thin, overlapping baleen plates. This process leaves behind a large volume of krill, which gets consumed by the whales. Blue whales are found in all the oceans, except the Arctic. They occasionally swim in small groups but they move about in pairs or stay alone.

They now face a severe threat due to whaling and are considered endangered according to the IUCN Red List.

Picture Credit : Google

Whale sharks are the largest fish to be identified and can grow up to 10 metres in length. They consume a wide variety of sea animals and planktons in a rather interesting manner. They just keep their mouths wide open and scoop the tiny plants and fishes as they move close to the surface of water.

The whale shark belongs to the category of filter feeders, just like the world's second largest fish, the basking shark. This means that their huge jaws filter everything it comes across, to find its food. This mechanism is similar to that of the baleen whales, where too, a cross-flow filtration is observed. These giants prefer warm waters and are found in all tropical seas. They also migrate to the continental shelf of the central west coast of Australia during the spring season. During this time, the coral spawning of the Ningaloo Reef of this region provides the whale shark with plenty of plankton to feed on.

Although whale sharks are massive, they are very docile. They even allow swimmers to hitch a ride at times! Currently listed as a vulnerable species, these animals face the threat of hunting, as in some parts of Asia, people continue to hunt them.

Picture Credit : Google