Category Zology

Were the dinosaurs killed by more than one asteroid?

A newly discovered undersea crater off the coast of West Africa is leading scientists to wonder whether the dinosaurs were wiped out by more than one asteroid 66 million years ago.

What appears to be a second large asteroid impact crater has been discovered under the sea off the coast of West Africa, leading scientists to speculate that it may have been the smaller cousin of the one that struck the gulf of Mexico millions of years ago, wiping out the dinosaurs.

At 9km wide, the newly discovered crater- dubbed the Nadir Crater – is not as larger as the vast Chicxulub Crater in Mexico, which is estimated to be around 180km wide and 20km deep.

However, its size, age and placement on the other side of the Atlantic Ocean is leading geoscientists to wonder if the Earth was hit by more than one space rock that fateful day 66 million years ago, or if the Nadir Crater was caused by a chunk that broke off the Chicxulub asteroid.

Picture Credit : Google 

What is guano?

Guano is the accumulated excrement or droppings of seabirds or bats. It is valuable as manure, as it has a high content of nitrogen, phosphate and potassium – key nutrients essential for plant growth. Before fertilizer began to be made in factories (the first such factory came up in Germany in 1913), countries competed to capture islands populated by seabirds so that they could have access to large deposits of guano. Economies of some countries like Peru flourished through the export of guano. Even today, Peru is the largest exporter of guano which is in demand again because of the growing popularity of organic farming.

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ARE CHEETAHS COMING BACK TO INDIA?

Cheetahs to prowl India for the first time in 70 years! The country will be home to the world’s fastest land animal for the first time since 1952, when the indigenous population was declared extinct.

Eight cheetahs are set to arrive in August from Namibia, home to one of the world’s largest populations of the wild cat. The first arrivals will make their home in the State of Madhya Pradesh at Kuno-Palpur National Park, selected for its cheetah-friendly terrain.

Separately, India is also expected to get 12 cheetahs from South Africa, for which a draft agreement has already been signed, with a final one expected soon, officials familiar with the matter said.

The Asiatic cheetah could once be found in areas stretching from the Arabian Peninsula to Afghanistan. It is now known only to survive in Iran, where in 2022 only 12 were reportedly still alive.

Only about 7,000 cheetahs remain in the wild globally, with most of them in African savannahs. The animal is classified as a vulnerable species under the International Union for Conservation of Nature’s red list of threatened species. The arrival of the cheetahs is expected to coincide with India’s 75th Independence Day celebrations on August 15.

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HOW ARE MAMMALS DIFFERENT FROM OTHER ANIMALS?

All mammals have fur on their bodies – hair is a form of fur – and they are warm-blooded. This means that they are able to keep their body temperature stable even if there are changes in their environment. Most begin life inside the mother’s body and are born as well-formed babies. Mammal babies feed on their mothers’ milk until they are old enough to eat solid foods.

Animals belong to the kingdom Animalia while mammals belong to the class Mammalia. Development from a blastula, consumption of organic material, breath oxygen, motility, and sexual reproduction are the characteristic features of animals while the fur-covered body, sweat glands, three ear bones, single lower jaw bone, neocortex, uterus, giving birth to live young, and mammary glands are the characteristic features of mammals. Vertebrata, Protochordata, Echinodermata, Mollusca, Arthropoda, Annelida, Nematoda, Platyhelminthes, Coelenterata, and Porifera are the animal phyla while placentals, marsupials, and monotremes are the three types of mammals. Animals are multicellular eukaryotes, which develop from a blastula. They consume organic materials and breath oxygen. Mammals are the most developed groups of animals whose body is covered with fur. They have mammary glands and they give birth to the live young. The main difference between animals and mammals is the characteristics.

Similarities Between Animal and Mammal 

  • Animal and mammal are two types of higher organisms classified under kingdom Animalia.
  • They are multicellular eukaryotes.
  • Both grow from a hollow cell sphere called blastula.
  • Both consume organic materials.
  • They breath oxygen.
  • They are motile and undergo sexual reproduction.

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WHAT ARE THE FUN FACTS ABOUT MAMMALS?

Mammals are vertebrates – animals that have a backbone. This means that all mammals have a bony skeleton inside their bodies, which gives them a strong frame. They usually have two pairs of limbs, and organs such as a heart, lungs, stomach and intestine. They come in all shapes and sizes and live in a huge variety of places, from the frozen Arctic wasres to the hottest deserts on Earth.

Of all the different types of animals, mammals are the ones that humans can relate most closely to. This is because humans are just one of the many species of mammals. So what are their characteristics? How are they alike and what are their differences?

They Produce Milk

All mammals have mammary glands, which are used to provide milk for their young. Mammary glands are made up of glandular tissue and ducts and develop from the sweat glands. While many have nipples that allow their young to nurse, one family of mammals, known as monotremes, secrete milk through ducts rather than nipples.

In nearly all mammals, the female is the only one who feeds the young. This means that the nipples of the male, while present, are underdeveloped. In a few species of mammals, such as the Bismarck masked flying fox and Dayak fruit bat, both the male and female are capable of producing milk and both will help care for the young.

They Are Warm-Blooded

A warm-blooded animal is better able to regulate its internal temperature, making it more resilient to outside threats. While a cold-blooded reptile requires a certain external temperature to function, warm-blooded mammals can maintain their body temperature through diet and other methods.

They Have a Four-Chambered Heart

One characteristic of mammals that you cannot see is their four-chambered heart. Reptiles and amphibians have three-chambered hearts, while fish have hearts with two chambers. Birds and mammals are the two classifications of vertebrates that have four chambers.

With a four-chambered heart, the body can easily keep the deoxygenated blood heading to the lungs separate from the oxygen-rich blood heading away from the lungs. This means the animal has fully oxygenated blood available at all times. By having constant access to a well-oxygenated supply of blood, mammals are able to physically exert themselves more fully and without the need for frequent breaks.

Most Replace Their Teeth Once Over Their Lifetime

With the exception of a few mammals, such as kangaroos and manatees, mammals replace their teeth once over their lifetime. Born with deciduous teeth, these fall out to make room for the primary teeth. If they lose a primary tooth, it doesn’t grow back. This contrasts with animals such as alligators and sharks, that can replace teeth throughout their life.

Their Lower Jaw is Made of a Single Bone

In other classes of vertebrates, the lower jaw is made up of several bones and is not attached to the skull. The mammal’s jaw is made of a single bone, attached to the skull. This solid structure gives the mammal’s jaw tremendous power.

They are Protected by Hair

All mammals have some form of hair or fur during some period of their life. Some, like dogs and cats, are covered in fur throughout their life. Others, such as dolphins, have a light covering of hair early in development.

Hair can provide camouflage, protection from the weather, and aid in exploring their environment.

Credit : A-Z Animals 

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HOW BIG IS THE LEATHERBACK?

The largest of all the turtles is the leatherback, which can grow up to 1.6 m long and weigh about 360 kg – almost as heavy as a horse. Unlike other turtles, its shell is not hard but slightly flexible with an almost rubber-like feel. It can stay underwater for over an hour and dive to a depth of about 1280 m.

The leatherback sea turtle is the most unique of all sea turtle species. As the only living member of the family Dermochelyidea, they are the largest living turtle species and have the greatest migratory distribution of any reptile on the planet. Its distinguishing feature is its carapace, which has a smooth, leathery skin that covers a flexible matrix of bone. This carapace is highly specialized for diving to extreme depths of up to 4,000 feet (1,219 meters). In addition, a unique thermoregulatory adaptation allows leatherbacks to maintain core body temperatures at these extremely cold depths.

Adult leatherbacks have few natural predators, but their eggs and newborns are preyed upon by many animals, including birds, raccoons, and crabs. Female leatherbacks tend to return to the same nesting area to lay their eggs. Their large size makes them opportunistic in selecting a nesting beach. Like most reptiles, temperature determines the gender of the offspring—if it’s warm inside the nest, females will be born. Likewise, if temperatures are cooler, males develop. Once the eggs hatch, they’re on their own—the baby sea turtles must make it into the water and learn to fend for themselves without any care from their parents. Leatherbacks reach maturity at approximately 16 years old. Their average lifespan is unknown, but it’s thought to be at least 30 years.

Leatherbacks are found in tropical and temperate marine waters all over the world. They live off both the east and west coasts of the United States, and also in Puerto Rico, the Virgin Islands, and Hawaii. Leatherbacks spend most of their lives at sea and sometimes look for prey in coastal waters.

Jellyfish make up the biggest portion of their diet, but they also eat seaweed, fish, crustaceans, and other marine invertebrates. Leatherbacks have downward-pointing spines in their throat, which allows jellyfish to be swallowed, but prevents them from coming back up.

Credit : The National Wildlife Federation

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