My Science School

Grizzly bear is a subspecies of the brown bear, found in North America and Canada. It has brown fur, but hairs on the shoulders and back has streaks of white which give them the "grizzled" look. It also has a hump on its back. Its diet includes berries, leaves, nuts and fish, rodents and moose. Hibernation lasts between 5 and 8 months. It is a great swimmer and runner. It has an excellent sense of smell.

Grizzly bears have become "famous" thanks to pictures of them catching salmon in shallow rivers, such as in the streams of the Kodiak Archipelago of Alaska. However, due to climate change, some bears are switching from eating salmon to eating elderberries, as early warming causes the berries to bloom prematurely. Because bears in the archipelago previously ate up to 75 per cent of a salmon population in a region, researchers believe the dramatic increase in salmon populations will disrupt the entire food chain on the islands. For example, fish carcasses not only enrich the soil around rivers, they also provide an important food source to other animals.

Although grizzly bears eat a variety of different insects, moths are available to them in large numbers. Grizzly bears have been seen moving through boulder fields and turning over heavy rocks to feed on masses of army cutworm moths. A grizzly bear in Yellowstone National Park was seen to have consumed over 40,000 moths in one day. However, eating this many in a day is uncommon.

Canada is famous for its grizzly bears. Unfortunately, however, grizzly bears have been assessed as a species of special concern, meaning they could become threatened or endangered in the future. They are threatened by climate change, unsustainable hunting, habitat loss and extremely low reproductive rates. There are about 33,000 grizzly bears in the U.S. (mainly in Alaska) and about 26,000 grizzly bears in Canada (mainly in BC). Hopefully, Canadians are willing to protect grizzly bears and their habitat, because a future without these amazing animals would, indeed, be unbearable.

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Skunk is a mammal that lives in North and Central America. It is easily recognised by its black and white fur. But some of them are brown or grey. All of them are striped, even from birth. It is an omnivore, enjoying a wide variety of fruits, insects, worms, reptiles and rodents.

It is known for releasing an odorous substance when threatened. This substance is not harmful to the victims, but they will not be able to get rid of the smell for a couple of days. It is not a true hibernator, but do den up for extended periods of time and remain inactive and feed rarely during winter.

Some species of skunk even spring into a handstand before spraying, which puts the skunk's warning markings on full display. If the person or animal doesn’t retreat, the skunk aims the spray at the eyes, allowing the skunk to escape. The spray can remain on its target for days.

Skunks are nocturnal, which means they search for food at night and sleep in dens lined with leaves during the day. Their favorite foods include fruit and plants, plus insects, bird eggs, small rodents, and birds. Birds like the great horned owl prey on skunks. Scientists believe it’s because the birds don’t have a very good sense of smell, which makes the skunk’s spray useless in an attack.

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Most animals grow old and die. But there are a few exceptions such as the hydra. A tiny, soft-bodied freshwater animal, the tentacle hydra remains youthful because of its regenerative abilities. It carries powerful stem cells which are capable of continuous division, making the hydra renew its body with fresh cells.

Unlike most animals that must worry about old age, disease, or losing a limb, a hydra can constantly replace damaged parts of itself. In certain cases, an entirely new animal can grow from a detached chunk of hydra tissue. On average, they replace all their cells every 20 days, reports Discover magazine’s Katharine Gammon.

Though earlier studies have uncovered some of the secrets behind hydra tissue regeneration, researchers are still looking for answers about how the animal directs its cells to sprout a new head where one was lost. Learning more about the process of regeneration in animals like hydra could potentially lead to new insights about human development, too. In an effort to understand the genetic basis behind the ability, Mortazavi and his colleague Aide Macias-Munoz looked at which genes are switched on and off during head regeneration and how those genes are controlled.

Credit : Smithsonian 

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The day

On December 20, 2013, the United Nations General Assembly proclaimed March 3 as UN World Wildlife Day "to celebrate and raise awareness of the world's wild animals and plants". March 3 was chosen because that was the day way back in 1973 that the Convention on International Trade in Endangered Species of Wild Fauna and Flora was signed. The theme for 2022 is "Recovering key species for ecosystem restoration". The day aspires to "drive the debate towards the imperative need to reverse the fate of the most critically endangered species, to support the restoration of their habitats and ecosystems and to promote their sustainable use by humanity".

Recovering key species

The day aims to turn the spotlight on "the conservation status of some of the most critically endangered species of wild fauna and flora". Small or large, each and every creature on the planet has a unique function. No matter which part of the world we are in, as humans we are dependent on animal and plant biodiversity for our very existence. We rely on them for everything from food and medicine to clothing and housing. So, a species going extinct affects not just the species, also us humans. This is because when species disappear, ecosystems too disappear. How does that happen?

Ecosystem restoration

 As mentioned earlier, every organism has a vital role to play in an ecosystem Any ecosystem is carefully balanced and is a web of interconnected species of animals and plants. When one of them goes extinct, animals and plant dependent on that species in some way-for food, shelter, nest. etc. - will have to find a new place for these benefits or suffer. Eventually, if the earlier balance cannot be achieved the ecosystem collapses. Take the case of the bees. Bees play an important role in pollination, because of which new plants are born. If bees go extinct, gradually most plants will disappear, and along with them the herbivores that eat the plants, the carnivores that eat these herbivores, and so on. Further, humans too will be left without plant-based and animal-based food. No honey, for sure! This is why it is important to protect species, especially critically endangered ones, from going extinct. When such species are protected, the ecosystems are protected too. Several aspects, including deforestation and habitat loss push species to extinction, and by protecting our environment, we protect the species around us, ourselves, and the planet itself!

Threatened Species In Numbers

• According to data from the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, over 8,400 species of wild fauna and flora are critically endangered.
• Close to 30,000 more are understood to be endangered or vulnerable.
• Based on these estimates, it is suggested that at least one million species are threatened with extinction.

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A pet passport is a document which allows a pet animal to cross international borders without being quarantined or subjected to veterinary testing. Pet passports were first introduced in Great Britain in 2000 under the Pet Travel Scheme or PETS to make travelling with pets easier and less stressful for owners. Earlier, there were strict rules of quarantine of up to six months for any pet animal entering the country to keep out rabies and other infectious diseases. If a quarantined animal was found infected, it was either destroyed or deported.

Over time, PETS was extended to other EU countries, the United States, New Zealand, Australia and several nations around the world, including India.

 A typical pet passport has a picture, description and information about the pet and its ownership. It has details of the animal's microchip or identification tattoo, proof of rabies vaccination and blood tests confirming the presence of rabies antibodies, signed by a registered veterinarian. In some countries, pets must also show proof of treatment for ticks, fleas and tapeworms and additional vaccinations.

Without these documents, the animal could be detained at the border and quarantined, with the owner paying the costs of quarantine, boarding and veterinary examination fees.

The first pet to be allowed into UK under PETS was Frodo Baggins, a pug.

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Giant clams are iconic megafauna. And these creatures face several threats now. What are they?

Though the term megafauna is generally accepted and used to refer to large creatures, research papers have claimed that it sometimes includes smaller creatures and that there may not be any specific scientific approach for defining megafauna. Irrespective of the lack of clarity in the definition, giant clams have been classified as megafauna. Calling coral reef their home, giant clams are the largest aquatic mollusc on Earth, weighing up to 250 kg and one metre long.

They are found in the Indo-Pacific waters, and common in Australian waters. However, the same cannot be said of other regions. Their populations have been over-exploited for meat and shells. Some are said to have gone extinct locally. And so, not surprisingly, nine giant clam species have long been included in the IUCN's Red List of Threatened Species.

It is said that breeding programmes for more than 30 years have helped rebuild over-exploited wild populations in the Pacific Islands, Southeast Asia, and Japan. Even as the demand for their flesh and shell   continues, they're facing new threats "marine heatwaves and acidifying oceans" and "poor water quality and lower light levels caused by sediment-heavy run-off from cities and farms". Just like corals, giant clams have a symbiotic relationship with microalgae. When stressed (due to reasons such as warming waters), the giant clams expel these microalgae and turn white - they bleach, just like corals.

But does this mean giant clams will soon become a thing of the past? Not necessarily. While continuing the breeding programmes, researchers feel that finding new ways to manage clams on coral reefs "such as by seeking out possible new habitat for giant clams and breeding more resilient individuals" - can still save them from these threats. Other suggestions include aquaculture programmes that help baby clams get used to slightly warmer, more acidic and darker waters during breeding and rearing before transplanting them out to the wild" and offering the clams "symbiotic microalgae that are more tolerant to higher temperatures or light levels in early life". The best part? By protecting their habitat, we protect not just the giant clams but also corals, fish, and other invertebrates.

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The planet is home to billions of organisms and none of them (including humans) exists on its own. We are all dependent on each other for our survival. Symbiosis is the umbrella term used to refer to such interactions among animals, birds and plants of different species living together. There are five main symbiotic relationships: mutualism, commensalism, predation, parasitism, and competition Mutualism is the relationship where both the species benefit from each other, in commensalism one species benefits from another, while the other remains unaffected in predation and parasitism, one benefits by harming the other while a predator kills its prey immediately, a parasite lives at the expense of the host species and may kill it over time Competition is the struggle between different species to utilise the same limited resources Today, let’s take a look at some of the species that share mutualistic relationship with each other.

Zebra and Ostrich

Zebras and ostriches are perfect examples of friends having each others' back. Herds of zebras and of ostriches often travel across the open African plains together and they warn each other of danger. Ostriches have a poor sense of hearing and smell, while zebras have a poor eyesight. Zebras look out for potential threats to the ostriches by using their exceptional hearing skills, while the far-sighted ostriches stay vigilant towards the zebras predators by scanning the grassland and spotting threat from afar.

Clownfish and Anemone

There are 30 species of clownfish and all of them form a mutual relationship with anemones. They are even called anemonefish. A sea anemone is a predatory marine animal that lives attached to rocks and catches prey by injecting venom from its tentacles. Clownfish are immune to the anemones venom and actually live within their tentacles. While sea anemones provide protection to the clownfish, the fish clean the anemones tentacles, keeping them free from parasites. Clownfish also lure anemones prey towards the tentacles by acting like baits.

 Humans and Honeyguide bird

An African bird called the greater honeyguide is famous for sharing a friendship with hunters. It helps humans locate bees’ nests to harvest honey. Honeyguides give a special call to attract people's attention, then fly from tree to tree to indicate the direction of a bees' nest. While humans get honey, the birds get to feast on bee larvae and wax. Honeyguide perhaps consider humans useful collaborators because of our ability to control stinging bees with smoke and use tools to open the honeycomb, which the bird cannot do on its own.

Ants and Aphid

Several species of ants and aphids share a well-documented mutualistic relationship. Aphids are small insects that feed on the sap from plants and secret a sugary-liquid called honeydew. This secretion is quite enjoyed by some species of ants. The ants milk the aphids by stroking them with their antennae and in return, the ants protect the aphids, pretty rigorously, from predators and parasites.

The ants ensure the aphids are well-fed. They move the insects to a new plant when the nutrients from the host plant are exhausted. Some species of ants go to the extent of destroying aphid predators' eggs. Some species of ants care for the eggs of aphids by transfering them to their own nest during winter. When the eggs hatch, the ants carry the newborns to host plants to feed. They secret the sugary meal for the ants and the cycle continues.

Bat and Pitcher plant

Pitcher plants are carnivorous plants that trap their insect preys by luring them with nectar. The unassuming insects fall down the slippery slope and eventually drown in the digestive liquid of the plant. While we might think it would be prudent for animals to avoid these plants, woolly bats voluntarily clamber inside the plants - to roost. They share a mutually beneficial relationship with the plants. So what does the plant get in return for subletting its comfy room to the mammal? Poop. The bat guano (waste) is rich in nitrogen, a crucial plant nutrient, you see!

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