Marine mammals prey on livers for buoyancy

In recent months, four bodies of great white sharks have washed up on the western shores of South Africa. Each shark’s liver had been “surgically” removed, along with the hearts in two of the cases.

Orca whale
By Minette Layne from Seattle, Washington, USA – Single breaching orca (cropped), CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=3351306

The culprit for these deaths has been determined to be orca whales, also known to live in that region where the Indian and Atlantic oceans meet. Orcas don’t often prey upon great whites, althought it isn’t unheard of. More frequently, they are known to consume the livers of the broadnose sevengill shark off the coast of California.

Also off California, sea lions hunt leopard sharks and also consume their livers.

The livers of sharks are very large, and contain fats which give them buoyancy; this is necessary as sharks lack the gas-filled swim bladder of bony fish. Eating these livers may help the predator’s buoyancy, as well as providing a nutrient-rich meal.

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Owning pets increases social capital

Social capital has been defined by political scientist Robert Putnam as the “connections among individuals, social networks and the norms of reciprocity and trustworthiness that arise from them”. In other words, feeling and behaving like part of a community.

Recent studies in the US and Australia have linked higher social capital to pet ownership in ways which go beyond what you might expect.

vastraWhile you might be familiar with the social interaction that walking a dog invites in the community, and it is true that of all pet owners it is dog-walkers who score the highest, the social capital of pet ownership goes beyond the obvious.

Social capital is higher in pet owners across the board, whether the pets are dogs or any other animal. This may be simply due to shared experiences and shared desires; having things in common is a large factor in any social experience.

But why is social capital important, and why should we care who has it? Social capital has been shown to have a significant impact on all sorts of issues, including mental health, educational outcomes, and crime deterrence.

So if you don’t already, go out and get a pet! (We here at Animals Worldwide support adoption from shelters!)

 

Shedding light on thirsty aardvarks

Porc_formiguer
By MontageMan is the author of the original image, I did the crop – Cropped from File:Porcs formiguers (Orycteropus afer).jpg, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=6358271

The aardvark is a solitary and secretive creature, making its home in sub-Saharan Africa, nocturnal and living underground. Lacking the reflective tissue that makes many other animals’ eyes shine in the dark, the aardvark is notoriously hard to track down and study in the wild.

It has long been presumed that aardvarks don’t drink water, instead obtaining all the fluid they need by metabolising their food: termites, ants, and a rare fruit called the aardvark cucumber.

However a recent study has finally put paid to this myth by compiling images, videos, and reports of aardvarks drinking in the wild. They drink in the same way that other ant-eating species do, by dipping their long noses into rivers and puddles.

In captivity aardvarks are often fed a dry diet, lacking access to water, which is detrimental to their health. Hopefully this new information on the shy animal’s drinking habits will ensure the introduction of water to their habitats in zoos.

Roman circuses used smaller ponies than previously thought

Roman chario
Img: British Museum

The recent discovery of a horse hoof at a Roman circus site at Colchester has changed our perception of the ancient Roman chariot races.

The bone is indicative of a much smaller horse than we usually imagine taking part in these chariot races, around the size of a Shetland pony (although not, as some news sources have reported, actual Shetland ponies). The ponies involved in these races may have been around 9 hands high. (A hand, in horse parlance, is 4 inches.)

Representations of chariot races from the period do tend to show horses relatively small compared to the men with them, but it was unknown whether this was a form of artistic licence, or an attempt to emphasise the men over the animals. Now, with this hoof bone discovery, we can be reasonably sure of these pictures’ accuracy in scale.

Investigations and excavations by the Colchester Archaeological Trust are ongoing.

Rare white moose photographed in Norway

The plural of moose is still just moose, not meese.

Two of the rare white moose were recently caught on camera in Norway. It is unclear whether these twin calves are albino (with red eyes, and usually sterile) or piebald (white with some brown or grey specks).

Either way, white moose are incredibly rare. Out of the roughly 1 million moose in the northern hemisphere, a white moose is only spotted every couple of years.

Coprophagia: Why animals eat their own feces

61696620_c1188ad4fc_m
Img: hiveminer.com

Have you ever seen an animal defecate, then turn around and eat its own feces? It’s more normal than you might think, and there is a reason.

Coprophagia, the act of eating poo, is practiced by many species, including primates, rodents, dogs, hippos, and baby elephants. The different types of animals have different reasons for this behaviour.

In lagomorphs (rabbits and hares), nutrient absorption from food occurs in the small intestine, prior to entering the large intestine where bacteria break down tough plant material. This means that the droppings of these creatures retain many nutrients which can be absorbed fully on the second time through the digestive system. Lagomorphs produce their edible feces, cecotropes, at night, meaning that many rabbit owners never see them; they’re already consumed by morning.

In other animals, such as elephants and hippos, babies eat the feces of fellow herd members, especially their mothers, during the weaning process. Between moving from their mother’s milk to solid foods, eating feces from family members helps establish healthy gut bacterial communities, which then assist with the digestion of solid foods.

In most other herbivores, the behaviour is explained by a need to extract as much nutritional value from their food as possible. The bacteria present in feces can be vital to the nutrient-extraction process.

In carnivores like dogs, the explanation is less clear. Even dogs fed high-nutrient diets still practice coprophagia. It may be done out of boredom, or as an imitation of other domestic and familiar animals, especially their mothers.

The biggest insect the world has ever seen

Griffinflies
By Dodoni – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=2807299

Most modern insects are fairly small, compared to their ancient forebears. It might be hard to believe when you’re freaking out over the size of a cockroach or even a rhinoceros beetle, but these guys have got nothing on the ancient Meganisoptera order of insects.

In the early Permian period, 299-251 million years ago, dragonfly-like creatures called Meganeuropsis permiana fluttered gracefully – I presume – over the earth. These amazing insects had a wingspan as wide as 28 inches, and bodies up to 13 inches long.

At that time on Earth, oxygen levels in the atmosphere were considerably higher than they are today. It is believed that these higher oxygen levels allowed for the evolution and effectiveness of megafauna of all types, and that the decrease in modern times partially explains why animals no longer grow so enormous.

The ibis in Ancient Egypt

Sacred Ibis
By Steve Garvie from Dunfermline, Fife, Scotland – Sacred Ibis (Threskiornis aethiopicus)Uploaded by Snowmanradio, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=12687024

This is an essay I wrote for university a little while ago about the importance of the Sacred Ibis to the culture of the Ancient Egyptians. It includes references, so if you want further information it’s easy to find!

Sacred Ibis in Ancient Egypt

Chickens help explain human vision

Chickens
By Andrei Niemimäki from Turku, Finland – Friends, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=3769100

Humans are one of a small group of animals with detailed colour vision in the daytime. This is due to a small spot in the centre of the retina, called the fovea.

However the cause and process behind the formation of the fovea has been something of a mystery until now. A new study on chickens has revealed that the existence of the fovea is dependent on the suppression of retinoic acid, a form of vitamin A.

As well as increasing our understanding of how high visual acuity developed in humans, this new insight could help combat macular degeneration, a leading cause of vision loss.

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