Category Zology

The science behind pronghorn’s speed

When we think of very fast land animals, the first one that comes to our mind is perhaps the cheetah. Why not? It is the fastest land animal! Do you know which one is the second fastest? The pronghorn. And, the theory behind how it developed such. speed is fascinating. Let's find out more about the animal and its sprinting capacity.

A hoofed mammal, the pronghorn is native to North America, and does not have any close relative anywhere in the world. Healthy populations of the animals exist in their range and are listed under 'Least Concern' in the International Union for Conservation of Nature Red List of Threatened Species. Though it looks a lot like an antelope, the herbivore belongs to its own taxonomic family called Antilocapridae. Pronghorns get their name from the forward-facing projection – the prong on their horns. Interestingly, their ‘horns’ exhibit characteristics of both a horn and an antler. The sheath of its horn is made of keratin, the substance horns are made of. But, these horns are forked and shed every year-just like antlers are! While much can be written about what else is unusual about the pronghorn, its most unique characteristic is its speed.

Running at more than 80 kmph, the pronghorn is the fastest land mammal in its entire natural range- from Canada through the US to Mexico in one aspect, it even gets better than the African cheetah-it can maintain a fast speed for a longer period of time than those carnivores. But the pronghom has no natural predator to match this speed, and so scientists had been stumped by the need for this speed. This is where the science of evolution comes in.

According to a study published recently, during the Ice Age, North America was home to several mammals that no longer exist today. Some of them are well-known today – woolly mammoths, giant sloths, and saber-toothed cats. There were lesser-known ones too, such as ‘Miracinongs’ a cheetah-like cat. The skeletal remains of ‘Miracinonyx’ show that “this now-extinct cat shares the morphological characteristics that indicate high speed capabilities with its African counterpart, the cheetah (Acinony)”. It is a close relative of the puma and the African cheetah. Both puma and ‘Miracinonyx’ are native to North America. Results provide support to "the hypothesis that ‘Miracinonyx’ preyed upon Antilocapra, but not exclusively”. Though it is not seen as conclusive evidence and more study is required, scientists say this "may provide an explanation for why pronghorns are so fast. Maybe they were chased by cheetahs after all".

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Glass frogs have a secret!

Glass frogs live on trees, are active at night, and many of them are difficult to spot because of their green skin that merges well with their environment. “But these amphibians become true masters of camouflage during the day when they’re asleep.” How? Come, let’s find out.

When glass frogs rest or sleep, their muscles and skin turn transparent. So, whats visible are their eyes, bones, and internal organs. It is hard to spot them because they sleep on the bottoms of huge leaves and also blend well with the environment due to their transparency. But, how do they turn transparent, and what about the visibility of blood? Red blood cells absorb green light (the colour of light usually reflected by plants and other vegetation), and reflect red light. This makes blood highly visible, especially against a bright green leaf. In the case of glass frogs, though, something extraordinary happens.

A research team recently “observed that red blood cells seemed to be disappearing from the circulating blood” when the frogs rest. They conducted additional imaging tests on the animals, proving via optical models that the animals were able to achieve transparency because they were pushing red blood cells out of their vessels. It was suspected that the cells were being stored in one of the frog’s inner organs. which are packaged in a reflective membrane.

To find out where exactly the blood was going, scientists used a non-invasive imaging technology called photoacoustic microscopy (PAM). And the result was startling. The primary result is that whenever glass frogs want to be transparent, which is typically when they’re at rest and vulnerable to predation. they filter nearly all the red blood cells out of their blood and hide them in a mirror-coated liver – somehow avoiding creating a huge blood clot in the process.” When the frogs “are awake, stressed or under anaesthesia their circulatory system is full of red blood cells and they are opaque”. This unique capacity would explain why there are hardly any other land-based vertebrates that can achieve such transparency.

Also, in “most animals, pooling blood together leads to clotting which can be life-threatening, for example = leading to heart attacks in humans”. So, studying these amphibians can even help us understand blood clotting better.

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Our connection to other mammals

What makes us humans different from our ape cousins? Well, our brain power. And, that came about through tweaks in the genes, according to an ambitious project, whose results were published recently. Come, let’s find out more about this, and also how we are similar to and different from other mammals.

The Zoonomia Project compared the genomes (the genetic material that makes up a living organism) of 240 mammal species, including humans, to trace evolutionary changes over 100 million years. It studied a wide variety of mammals-from the huge North Pacific right whale (59 feet long) to the tiny bumblebee bat, just 3 cm long. It also included our closest evolutionary relatives – chimpanzees and bonobos. Do you know what startling result the study threw up? “The researchers identified genomic elements- 4,552 in all – that were pretty much the same across all mammals and were identical in at least 235 of the 240 species, including people.” It means that certain parts of genomes have remained unchanged across all mammal species, humans included, over millions of years of evolution.

As for how humans are different from other mammals, the study points to areas “associated with developmental and neurological genes”. It suggests that when Homo sapiens evolved, it involved changes in how the nervous system genes were “regulated”. And these were just tweaks rather than any dramatic and major changes to the genes themselves. This explains why we still share a large part of our genetic makeup with our ape cousins.

And, genes are also responsible for traits unique to some mammals. For instance, hibernation and the sense of smell. While some mammals have a keen sense of smell, others have almost none. Humans are “somewhat average”. The study also saw changes in genetic sequences in some species “in relatively short periods of time”, indicating how they are adapting to their environments.

While the findings are fascinating by themselves. scientists believe they “could inform human therapeutics, critical care and long-distance space flight”, and “also can help identify genetic mutations that lead to disease”.

In a study, researchers identified genomic elements – 4,552 in all-that were pretty much the same across all mammals and were identical in at least 235 of the 240 species, including people. It means that certain parts of genomes have remained unchanged across all mammal species, humans included, over millions of years of evolution.

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Does owls have eyeballs?

Owls don’t have eyeballs. They have eye tubes or cylinders, rod-shaped eyes that do not move in their sockets as eyeballs do. Instead, owls have to move their bodies or heads in order to look around. Since moving their torsos would likely make noise that would alert their prey to their presence, owls have evolved to have necks that can spin up to 270° essentially silently.

But why favour neck-spinning over the seemingly simple eye ball-spinning method of looking around? Well, night vision requires large corneas that allow for light to be collected effectively even in the dark, which is why most nocturnal animals (like the slow loris or tarsier) have huge eyes. But owls have small skulls, so their big eyes couldn’t expand out. They instead developed into the rod shape of today’s owls. They aren’t alone though: some deep-sea fish (like the anglerfish) also have rod-shaped eyes for seeing in the dark.

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Why do epaulette sharks walk on land?

Researchers at a Florida university say a species of shark with the ability to walk on land is evolving to survive warming seas and the climate crisis.

The epaulette shark, found on shallow reefs of Australia and New Guinea, can walk for upto 90 feet on dry land using its paddle-shaped fins, and survive hypoxia (deficiency of oxygen) for up to two hours. The 3 foot long sharks are able to slow and fast walk, as well as swim, giving them an exceptional ability to cross land to reach more favourable environments.

Tide pools and coral reef environments are subjected to warm temperatures when the tide is out. These sharks can move from tide pool to tide pool, allowing them to access new pools to forage for food or tide pools with better oxygenated water.

What sets epaulette sharks apart from other shark species with these abilities, is their tolerance of hypoxia for a prolonged period, and ability to not only survive being on land but walk distances up to 30 times its body length. This gives them better agility to evade predators, reach areas with more plentiful food and less competition for it.

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Will there be a ‘Project Great Indian Bustard’?

Proposed on the lines of Project Tiger, the country’s highest court seeks the government’s view on the idea. What prompted this? Here’s the story and background in five simplified points.

  1. THE PROPOSAL: Coming to the rescue of the critically endangered Great Indian Bustard (GIB), the Supreme Court has mooted the idea of launching ‘Project GIB’ on the lines of ‘Project Tiger. A bench headed by Chief Justice D.Y. Chandrachud, and comprising justices A.S. Bopanna and V. Ramasubramanian, also sought reports from the chief secretaries of Rajasthan and Gujarat in six weeks on the installation of bird diverters in priority areas and assess the total length of transmission lines in the two States where undergrounding of electric wires have to be done to ensure the birds do not die of electrocution.
  2. COMMITTEE FORMED: The Supreme Court had earlier set up a three-member committee to assess the feasibility of laying high-voltage underground power cables. It had also directed the Gujarat and Rajasthan governments to convert overhead electric cables into underground power cables, wherever feasible, and install bird diverters in priority areas where the birds live. It has now directed the committee to submit an updated status report on the steps to safeguard the birds.
  3. ENDANGERED SPECIES: The great Indian bustard, considered India’s most critically endangered bird species, is especially found in Rajasthan and Gujarat, and as per the 2021 report of the International Union for Conservation of Nature (IUCN), they are on the verge of extinction with less than 249 of them alive. Endemic to India, these birds were once seen across several States in the country. Due to hunting, habitat loss, and accidents caused by windmills and overhead power lines, their numbers dwindled over the last few decades.
  4. RECENT DEATHS: Being hit by overhead power lines is one of the major reasons for the death of these birds today, which is why the focus is on undergrounding such lines. While the work for undergrounding power lines has started in Gujarat, that does not seem to be the situation in Rajasthan, according to reports. Bird diverters too have not been installed in priority areas despite the Supreme Court’s direction. This would explain the deaths of seven birds so far this year, which is a matter of continuing concern.
  5. PROJECT TIGER: The Central government had launched ‘Project Tiger on April 1, 1973 to promote the conservation of the big cat whose population had dipped alarmingly. The number of tigers in 1973 was less than 300, and according to the All India Tiger Estimation Report, that number rose to 2,967 in 2018. Project Tiger has been viewed by the government as one of the most successful conservation programmes for a single species in the world. And so, it is hoped that a similar project for this critically endangered bird species would save it from extinction.

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