What is the difference between male and female walruses

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The species name is derived from the Scandinavian word for walrus. Walruses are found along the coast of the Arctic Ocean, where they spend most of their time on the seasonal pack ice. If ice is unavailable, they will gather on land. They have bred as far south as Nova Scotia, the Aleutians, and the White Sea, and stray individuals have been recorded in more temperate waters, including coastal Massachusetts, Ireland, southern England, France, and even northern Spain. Among the seals, the walrus is second in size only to the elephant seal.

It varies in size according to location; the smallest walruses are found in Hudson Bay, the largest in the Bering and Chukchi Seas. Hudson Bay males average 9. In the Bering Sea population, the adult males are about It is impossible to mistake a walrus for anything else. Its distinctive tusks are present in both sexes. Photograph by Charles Krebs. Stock Market. Reproduced by permission. The tusks are derived from the canine teeth, and they grow throughout life.

The tusk is almost purely dentine ivory ; this has made the walrus a target of hunting. Although fearsome weapons, the tusks are mostly used as ice axes, when the animal hauls itself out of the water onto an ice floe.

They are also used as a social signal, much like the antlers of deer. The size and shape of tusks differs between males and females, so it is likely that walruses use these clues to determine sex and age. Through emergency defecation, a sperm whale can disperse a smoke screen of shit into the water before the cetacean makes its escape.

Waving its tail to disperse their poop creates an underwater "poopnado," as Canadian diver Keri Wilk called it. These enormous diarrhea clouds also help recycle nutrients and store immense amounts of carbon, mitigating some effects of climate change. The larvae of the tortoise beetle are the Captain America of the animal kingdom — because they make shields out of poop.

Using their maneuverable anus that sits on their flexible rear end, they deposit their dung defense on their back. The fecal armor, made in part from the larvae's shed exoskeleton, can double as a club to whack off potential predators. Some beetle species can swing their poop shields around to hit predators with them. And some of the poop is shed exoskeleton, in order to retain any toxins that the beetle may have.

The Green Woodhoopoe takes a rather straightforward approach to defense. Young birds will simply coat themselves in liquid poop, using the odor to deter — or gross out — would-be predators. You wouldn't want to eat a poop-slathered bird now, would you?

From our perspective on Earth, most stars look like tiny, twinkling dots. But what color would a star be if you could actually see it up close? Most astronomy textbooks will clearly say hot stars are blue, and colder stars are red. These colors come from an idealized version of the light a star gives off, called a blackbody curve. New research published in Research Notes of the American Astronomical Society calculated colors of stars based on their actual energy distributions and the response of the human eye.

Smaller stars, like K and M stars , are beige instead of red. These cool sub-stars are purple because absorption by molecules in their atmospheres takes out a whole chunk of their visible light, leaving only red and blue light for us to see. There are a few more complexities that could change the color a star appears to us. Oxytocin earns its loving nickname because the brain releases the hormone during moments of social bonding, such as those between a parent and child or romantic partners.

But beyond this role, oxytocin has long been thought to play a more direct role in social circuit development, and a recent study published in the Journal of Neuroscience put this idea to the test with zebrafish.

Zebrafish are social creatures with evolutionarily similar brain circuitry to humans. Scientists can genetically alter them before observing their behavior across an entire lifespan, making them ideal for studying social behavior. So to understand the role of oxytocin-producing neurons in social brain development, researchers selectively removed those neurons from their brain circuits early in life and examined the consequences to social behavior once the zebrafish reached adulthood.

The researchers evaluated the zebrafish behavior by first separating a fish from a larger group with a transparent barrier, then observing how the lone fish reacts to its isolation. Like a person with FOMO "fear of missing out" from a party next door, socially healthy zebrafish stay close to the transparent barrier — seemingly longing to join the group on the other side. However, zebrafish with a disrupted social circuit explore their own tank with no preference to socialize.

Researchers found that zebrafish with their oxytocin neurons removed early in life showed less preference to socialize as adults. However, eliminating these cells in adulthood did not affect social behavior, suggesting that oxytocin shapes the social circuit early in life during a critical developmental window. They also found that removing oxytocin neurons early impaired other social brain components, including those required for attention, decision making, and reward.

Together, this suggests that the famous "love hormone" may define our long-term social preferences early in life. But unlike a Pixar movie, fish are not humans, and there is still more to learn about social brain development. Tool making is a complex behavior that, until recently, had only been confirmed in three species of primates including humans , and in some birds, including captive Goffin's cockatoos.

Now, a research group at the University of Vienna that has studied Goffin's cockatoos for decades has also observed the behavior in wild cockatoos. This species of cockatoo, a member of the parrot family, is comparable to three-year-old humans in terms of intelligence.

But before now, tool making behavior has not been observed in wild cockatoos, which is necessary to confirm that a species is indeed capable of making tools and their tool use is not just an artifact of captivity. The group spent over hours observing wild birds in their natural habitat in the Tanimbar Islands, Indonesia, with no success in witnessing tool use and manufacture. They then moved on to a catch and release method, where they captured 15 individuals and placed them in temporary aviaries with many resources and a food option that finally encouraged more complex approaches to foraging: the Wawai fruit, or sea mango.

The cockatoos really like eating the seeds of these fruits and need to go through the thick skin and flesh of the fruit in order to reach the seeds.

Two of the 15 individuals manufactured and used tools to extract sea mango seeds. Those two birds made tools by removing fragments from branches and then modifying them with their beaks.

The researchers identified three different tool types: wedges, to widen the fissures to reach the seed inside the fruit; fine tools used for piercing the coating of the seed; and medium tools used for scooping the seeds. Furthermore, the tools were used sequentially, which the researchers believe to be the most complex example of tool use in a species without hands.

Both cockatoos proficiently manufactured and used the tools immediately after provided the Wawai fruit, suggesting they knew how to do that before capture.

The fact that only two individuals were observed using tools indicates that this complex skill is not found species-wide and therefore has to be learned as a result of opportunity and innovation. This finding broadens our understanding of tool making ability beyond just primates. The growth of modern giant clams is supercharged compared to growth measured from fossil clams. A recent study from the Red Sea has shown this, finding that growth lines from modern species are larger than those of fossils from similar animals dated to the Holocene and Pleistocene.

These increased growth rates appear to be related to higher amounts of nitrate aerosols in the modern atmosphere. These come from many different sources. Some are natural, such as lightnin g, biomass burning , and soil processing , but most are from anthropogenic activity like burning fossil fuels and agricultural fertilization.

This fast growth may seem like a good thing, but growth doesn't mean anything about the overall health of the clams. Additionally, aerosols may actually reduce the productivity of marine phytoplankton, which represent almost half of the world's primary production. The overall effects of nitrate and other aerosol pollution on global land and ocean cycles are not well understood.

They may appear to reduce global warming by improving carbon dioxide uptake and reflecting the sun's heat, but they contribute to poor air quality. We can congratulate today's super clams on their impressive growth. But in the long run, fewer emissions on our part are probably better for them. Photo by Tim Mossholder on Unsplash. One thousand years ago, archers rode horses across the landscape of Hungary.

They were probably intimidating, possibly threatening, and definitely adventurous, but just like equestrians today, they also fell a lot. These horse riders remain a mystery.

Who were they? Where were they from? When did they start riding horses? To answer these questions, an international team of scientists set out to find a way to identify horse riders from just their skeletons, using the fact that horse riders tend to fall. The researchers examined skeletons from a cemetery of well-known horse riders in Hungary dating to the 10th century CE.

Riders in the cemetery were identified by horse riding equipment and horse bones in their graves. However, scientists could not be sure that skeletons without artifacts in the Hungarian cemetery never rode horses. Therefore, they also investigated skeletons from another group of people from 20th century Portugal that definitely did not ride horses.

They found that upper body fractures were more common among riders, and that fractures of the clavicle collar bone were significantly more common among the Hungarian riders than the 20th century non-riders. To figure out if these fractures could be caused by horse riding, researchers turned to modern equestrians. Sure enough, fractures of the upper body, especially the clavicle, are some of the most commonly reported injuries in modern day equestrians.

The researchers argue that, in combination with other skeletal changes, clavicle fractures can be used to identify horse riders from just their skeletons. Being able to identify horse riders in the past could help researchers find the first horse riders, shedding light on the ways horse riding shaped human history. Humans aren't the only animals that step up to help others out of difficult situations.

In a study recently published in the journal Scientific Reports, Michaela Masilkova of the Czech University of Life Sciences and her colleagues described a boar's daring rescue of two young wild boars stuck in a trap.

Few animals show this kind of rescue behavior: to go out of their way to help other members of their species that are caught in a dangerous situation. Masilkova's team inadvertently caught an astonishing act of altruism on camera while conducting a separate experiment to monitor wild boar movement for the prevention of African Swine Fever.

The goal was to catch boars so the researchers could mark them individually. The researchers set up traps containing food as lure. Once lured inside, a boar would be caged in by logs that would roll off the top of the enclosure and bar the door shut.

One night the trap — operating as usual — snared two young boars. But the night took an unexpected turn when a new herd arrived at the scene. One adult female took particular interest in the captives' predicament. Over the course of 29 minutes, the female pushed against the logs and successfully moved it, allowing the young boars to escape.

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