Showing posts with label mammal. Show all posts
Showing posts with label mammal. Show all posts

Tuesday, April 23, 2024

MAMMOTHS LAST MEAL

One of the first scientific accounts of a well-preserved woolly mammoth, Mammuthus primigenius, frozen in Siberia described the meat as enticingly red and marbled but smelling so putrid that researchers could only tolerate a minute in its proximity.

Despite this initial review, numerous apocryphal tales exist of dinners made from centuries-old mammoths found frozen whole in clear blocks of ice. 

These accounts have not only enchanted the public but also heavily influenced early scientific thought on Quaternary extinctions and climate; many researchers resorting to catastrophism to explain the instantaneous freezing necessary to preserve palatable meat.

The possibility of cloning is now the major draw of frozen mammoths but the public remains curious about eating prehistoric meat, especially because some modern paleontologists have credibly described tasting mammoth and extinct bison found preserved in permafrost.

Although less publicized today, eating study specimens was once common practice for researchers. Charles Darwin belonged to a club dedicated to tasting exotic meats, and in his first book wrote almost three times as much about dishes like armadillo and tortoise urine than he did on the biogeography of his Galapagos finches.

One of the most famously strange scientific meals occurred on January 13, 1951, at the 47th Explorers Club Annual Dinner (ECAD) when members purportedly dined on frozen woolly mammoth. The prehistoric meat was supposedly found on Akutan Island in Alaska, USA, by the eminent polar explorers Father Bernard Rosecrans Hubbard, “the Glacier Priest,” and Captain George Francis Kosco of the US Navy.

This much-publicized meal captured the public’s imagination and became an enduring legend and source of pride for the Club, popularizing an annual menu of “exotics” that continues today, making the Club as well-known for its notorious hors d’oeuvres like fried tarantulas and goat eyeballs as it is for its notable members such as Teddy Roosevelt and Neil Armstrong.

The Yale Peabody Museum holds a sample of meat preserved from the 1951 meal, interestingly labelled as a South American Giant Ground Sloth, Megatherium, not Mammoth.

Green Sea Turtle, Chelonia mydas
The specimen of meat from that famous meal was originally designated BRCM 16925 before a transfer in 2001 from the Bruce Museum to the Yale Peabody Museum of Natural History (New Haven, CT, USA) where it gained the number YPM MAM 14399.

The specimen is now permanently deposited in the Yale Peabody Museum with the designation YPM HERR 19475 and is accessible to outside researchers. 

The meat was never fixed in formalin and was initially stored in isopropyl alcohol before being transferred to ethanol when it arrived at the Peabody Museum. DNA extraction occurred at Yale University in a clean room with equipment reserved exclusively for DNA analyses.

In 2016, Jessica Glass and her colleagues sequenced a fragment of the mitochondrial cytochrome-b gene and studied archival material to verify its identity, which if genuine, would extend the range of Megatherium over 600% and alter views on ground sloth evolution. Their results showed that the meat was not Mammoth or Megatherium, but a bit of Green Sea Turtle, Chelonia mydas. So much for elaborate legends. 

The prehistoric dinner was likely meant as a publicity stunt. Glass's study emphasizes the value of museums collecting and curating voucher specimens, particularly those used for evidence of extraordinary claims. Not so long before Glass et al. did their experiment, a friend's mother (and my kayaking partners) served up a steak from her freezer to dinner guests in Castlegar that hailed from 1978. Tough? Inedible? I have it on good report that the meat was surprisingly divine.

Reference: Glass, J. R., Davis, M., Walsh, T. J., Sargis, E. J., & Caccone, A. (2016). Was Frozen Mammoth or Giant Ground Sloth Served for Dinner at The Explorers Club?. PloS one, 11(2), e0146825. https://doi.org/10.1371/journal.pone.0146825

The image of the mammoth you see here is by the very talented Daniel Eskridge. To see more of his work, and indeed purchase it, head over to: https://daniel-eskridge.pixels.com/

Wednesday, September 21, 2022

VELOCIRAPTOR VERSUS MAMMAL

The thrilling scene you see playing out before you is a velociraptor about to make a meal out of a little brown rodent. Run, little ancestor!

Velociraptors were smallish dinosaurs around 2 meters or 6 feet in length. Even so, this 45-kilogram or 100-pound carnivore was an impressive hunter.

They ran on two very speedy back legs to catch and dine on reptiles, amphibians, insects, small dinosaurs and mammals. 
Velociraptor is a genus of dromaeosaurid theropod dinosaur. These adorable wee killers lived 75 to 71 million years ago during the latter part of the Cretaceous. Two species are currently recognized, although others have been assigned in the past. Velociraptors had large brains relative to their body size. They were likely not Einstein-level smart, but certainly smart enough to know you were likely hiding behind that rock. The Theory of Relativity had quite a different connotation in the Cretaceous. The charming artistic rendering you see here is by the very talented Daniel Eskridge.

Sunday, September 18, 2022

DARWIN'S TOXODON

Toxodon is an extinct large grazing mammal. The first Toxodon fossils were discovered by Charles Darwin on his visit to South America as part of his voyage on the HMS Beagle. 

Darwin wondered at the fossil's strange appearance as it seemed to share features with both rodents and rhinos. 

“Toxodon is perhaps one of the strangest animals ever discovered,” wrote Darwin. He first encountered the creature in Uruguay on November 26th, 1834. 

“Having heard of some giant’s bones at a neighbouring farm-house…, I rode there accompanied by my host, and purchased for the value of eighteen pence the head of the Toxodon.”

The beast’s skeleton, once fully assembled, was a baffling mish-mash of traits. It was huge like a rhino, but it had the chiselling incisors of a rodent—its name means “arched tooth”—and the high-placed eyes and nostrils of a manatee or some other aquatic mammal. “How wonderfully are the different orders, at present time so well separated, blended together in different points of the structure of the toxodon!”

Although Toxodon is not related to rodents, in 2015, it was discovered to be distantly related to rhinoceros. 

Friday, April 22, 2022

STRENGTH AND BEAUTY: ORCA MAX'INUX

One of the iconic animals of the Pacific Northwest are Orca or Killer Whales. These playful giants hunt and play in our local waters and all the oceans of the world.

This past week, there has been a pod hunting and playing in the waters near Maple Bay on Vancouver Island. It is wonderful and a wee bit unusual to see them so long in the same hunting grounds. This partially due to their normal hunting behaviour but definitely impacted by the relentless roar of the motors of whale watching boats.

I do like folk taking an interest in our wildlife. We are more likely to work to protect them if we get to know them. But hunting down a decent meal, courting a mate and rearing your young are challenging with all that racket going on. Imagine trying to cook dinner, play catch with your kid or make love to your partner with half a dozen looky-loos on a hovercraft watching your every move. A bit of attention is flattering but at some point that becomes creepy. 

And yes, whale watchers are meant to keep a healthy distance but that was certainly not the case with the crowd of boats this week. 

Not surprising then that the whales try to dodge the relentless spectators — expending energy on avoiding us instead of on the business of being whales... hunting, eating, rearing, mating. I share this so we do not forget ourselves and enjoy wildlife to our own amusement not realizing the impact we have.

Orca are toothed whales who hunt our waters for fish, squid, birds and aquatic mammals. They are the largest member of the Dolphin family who hunt and live amongst their family groups or pods. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, orca are known as max̱'inux̱. I do not know the word for orca in the language of the Quw'utsun Cowichan First Nation whose shores they are swimming near this week. 

These large marine mammals are easily distinguished by their black-and-white colouration, large dorsal fin and a sleek, streamlined body. You can often get a peek at their top fin and just enough of their distinctive white eye patch to identify them from a distance.

Up close, their colouring is equally lovely. When I was little, a few resident orcas would come up to our float house and rub up against the side to give themselves a good scritch. We used to offer to help them with this by lowering a deck broom and rubbing it along them. They would roll around playfully and seemed to enjoy it much the same way dogs and cats appreciate a good scratch. 

They show curiosity and intelligence when they look at you and understand that your intention was to help not hurt when the broom was offered. One of them did give the broom a gentle nibble and carried it off a ways but very politely returned it a few minutes later. 

Across their back and along their pectoral flippers is a nice glossy black, The exception is their saddle, a wee patch of greyish white just behind their dorsal fin.  

Whales breathe through their nostril or blowhole that sits in the centre of their forehead. The blow of mist you see in the photo above is this fellow breathing and pushing air out through his blowhole and some seawater along with it. 

Killer whales have a white patch under their heads (lower jaw), under each fluke and a patch along their rear edge as you move towards the tail. While these patches of white make them easier for us to see and identify them, they act as camouflage to those they are hunting in the water.

Their large bodies are streamlined (hydrodynamic), like a submarine, for moving through the water. Whales have flukes or a tail used for swimming. The flukes are moved in an up-and-down motion to accelerate. The dorsal fin acts like the keel of a boat; it keeps the whale from rolling side to side while swimming. They have pectoral flippers just behind the head. These pectoral flippers are used for steering, turning, and stopping.

Live in coastal and offshore waters; resident pods may frequent localized waterways (bays, sounds, etc.) whereas transient pods tend to cover more extensive, varied areas.

An extended clan of orcas, known as the Southern Resident Orca community, socialize and forage in the inland waters of Washington State and British Columbia. The population grows and lessens in relation to the overall Chinook salmon abundance. It may have been this pod that were playing off our shores this week. They are certainly in the neighborhood on and off.

Females (cows) reach reproductive maturity quite late in life at around 14 to 15 years. They give birth every three to ten years, following a 17-month pregnancy. In our local waters, these young join the pod and stay together their whole lives.

At birth, the 2.6 m long calves arrive able to swim and dive and grow quickly feasting on their mothers' milk for the first year of their lives. 

The newborns stay close to mamma, feeding and learning from her and from the close-knit members of the pod. Over the course of their lives, these newborns will grow from 120 to 160 kg up to 3,600 to 7,250 kg.

Like all dolphins, orcas use sophisticated biological sonar, called echolocation. Echolocation enables them to locate and discriminate objects underwater. The vocalizations within whale communities vary and each are different from those in other communities. The calls also bring the pods together over large areas of water when it is not possible for the whales to see each other.

When all goes well, orcas live to be a ripe old age. Some males have been known to live into their 40s and perhaps up to 60+ years old. Females have been known to live up to 90+ years old.


Tuesday, November 16, 2021

YOU ARE WHAT YOU EAT... OR CAN DIGEST


The old adage, you are what you eat, might be best amended to you are what you can digest. 

For all the mammals, you and I included, we need the amylase gene (AMY). It codes for a starch-digesting enzyme needed to break down the vegetation we eat. 

Humans, dogs and mice have record numbers of the amylase gene. The AMY gene copy number increases in mammal populations where starch-based foods are more abundant. Think toast and jam versus raw chicken.

A good example of this is seen when we compare wolves living in the wild to dogs from agricultural societies. Dogs split off the lineage from wolves around 30,000–40,000 years ago. 

Domesticated dogs have extra copies of amylase and other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet, allowing Fido to make the most of those table scraps. Similar to humans, some dog breeds produce amylase in their saliva, a clear marker of a high starch diet. So do mice, rats, and pigs, as expected as they live in concert with humans. Curiously, so do some New World monkeys, boars, deer mice, woodrats, and giant African pouched rats. 

More like cats and less like other omnivores, dogs can only produce bile acid with taurine and they cannot produce vitamin D, which they obtain from animal flesh. Also, more like cats, dogs require arginine to maintain their nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.

The amount of AMY and starch in the diet varies among subspecies, and sometimes even amongst geographically distinct populations of the same species. I was at a talk recently given by Alaskan wolf researchers who shared that two individual packs of wolves separated by less than a kilometre ate vastly different diets. This had me thinking about what we eat and it is mostly driven by what is on offer. 

Diet impacts our genetics and this, in turn, allows the fittest to eat, digest and survive. While wolves win the carnivore contest, they will still eat opportunistically and that includes vegetation when other food is scarce. Would they evolve similar levels of AMY as humans, dogs and mice? Maybe if their diets evolved to be similar. Likely. The choice would be that or starvation.

The evolution of amylase in other domesticated or human commensal mammals remains an alluring area of inquiry.

Reference: 

Amylase in Dietary Food Preferences in Mammals: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516957/

Saturday, November 13, 2021

ECHIDNA: MONOTREMES

This little chocolate nugget with his impressive claws is an Echidna. They are curious egg-laying mammals from Australia and Papua New Guinea. 

They have spines like hedgehogs and they are sometimes called spiny anteaters because they feed on ants, termites, earthworms and other burrowing prey with their long, tube-like tiny mouths, toothless jaws and sticky tongue. 

Their spines are golden brown to black for the most part, although a few albino echidnas have been found with pink eyes and white spines. These solitary mammals have mammary glands — and lay eggs.

To help them search for their prey in the soil, Echidnas are equipped with electroreceptors in their beaks which is similar to platypuses and this is not a coincidence. 

Even though echidnas are land animals, they evolved from amphibious ancestors similar to platypuses. They now have strong limbs and claws for digging and just by looking at them, it would be hard to figure out that their ancestors were not fully land animals. 

There is even more to it because mammals evolved from fish that have swim bladders homologous with lungs. They evolved these swim bladders because the ancestors of all fish, except cartilaginous fish, lived either in a shallow aquatic environment, periodically drying lake or swampy water, poor in oxygen. 

Fish evolved into amphibians and conquered land. These amphibious animals evolved the ability to lay eggs in a dry environment and eventually evolved into monotreme mammals which at first were land animals but they adapted to an amphibious lifestyle again, like platypuses. 

Echidnas made another full circle by evolving adaptations to land habitat and abandoned the aquatic habitat again.

Echidnas and platypus are the only egg-laying mammals, known as monotremes. These spiky cuties live about 15-16 years in the wild but have been reported to live as long as 50 years under the right conditions. If you see one in the wild, you can determine the sex by size (of the adults) with males being 25% larger than the females on average. Fully grown a female can weigh up to 4.5 kilograms (9.9 lbs) and a male can weigh up to 6 kilograms (13.2 lbs). 

Monday, September 20, 2021

SHORT-BEAKED ECHIDNA

This chunky monkey is a Short-beaked Echidna, Tachyclossus aculeatus, which grows to about the size of an overweight cat. They are native to Australia and New Guinea. 

Echidnas are sometimes called spiny anteaters and belong in the family Tachyglossidae (Gill, 1872). They are monotremes, an order of egg-laying mammals. 

There are four species of echidnas living today. They, along with the platypus, are the only living mammals who lay eggs and the only surviving members of the order Monotremata. 

Superficially, they resemble the anteaters of South America and other spiny mammals like porcupines and adorable hedgehogs. They are usually a mix of brown, black and cream in colour. While rare, there have been several reported cases of albino echidnas, their eyes pink and their spines white. Echidnas have long, slender snouts that act as both nose and mouth for these cuties. The Giant Echidna we see in the fossil record had beaks more than double this size.  

Like the platypus, they are equipped with electro sensors, but while the platypus has 40,000 electroreceptors on its bill, the long-beaked echidna has only 2,000. The short-beaked echidna, which lives in a drier environment, has no more than 400 at the tip of its snout.

Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme. Their ancestors were aquatic, but echidnas have adapted to life on land. Today, they weigh in at about 7 kg today but back in the Pleistocene, they were much larger. The Giant Echnida, Megalibwilia ramsayi was about 10% larger at 10 kg and Zaglossus hacketti was a whopping 30 kg. 

Fossil remains are relatively rare and sadly, incomplete, but they tell us potentially two other species of Echidna thriving in the Pleistocene. We also find Robust Echidna, Zaglossus robustus, in slightly older Miocene aged outcrops in a goldmine in Australia. The Giant Echnida's we find in the fossil record are relatives of the Long-Beaked Echidnas who live in New Guinea today.