#xatw

[xatw]

U need a reminder you’re not brand new

[mattyena]

This extinct animal of the week is the Camptosaurus! This dinosaur was present during the Late Jurassic found in Western United States. This guy was about 5 meters in length and is an ornithopod dinosaur. Its teeth ware suggests that this dinosaur snacked on tough vegetation. The phylogenetics of the Camptosaurus are debated- as most dinosaurs are- though the Camptosaurus is a ancestor to the Iguanodon, the famous ornithopod herbivore with large spiked thumbs in the early Cretaceous. It’s thumb had the makings of the large thumb seen in the Iguanodon. The anatomy of these ornithopod dinosaurs have been debated over the years, but scientists today generally agree that the Camptosaurus could switch between walking on all fours to running with two. As a defense to predators, the Camptosaurus relied on speed and would run away (lol relatable) and could run up to 15mph.Their hands were prehensile and used for grabbing at vegetation. 

Sticker here!

Sources: Pim, K. (2016). Dinosaurs- The Grand Tour: Everything Worth Knowing About Dinosaurs From Aardonyx To Zunicerotops (pp. 111). The Experiment.

[xatw]

You are what you repeatedly do

[mattyena]

This extinct animal of the week is the Steller’s Sea Cow! You may be thinking, “this is just a manatee Matty what’s so special about it??” Well I thought so too, until I saw the MASSIVE FUCKING SKELETON OF ONE

Here is someone excavating one. AND THAT’S JUST WITH THE BONES. Imagine how fat a manatee is and put that on this skeleton, this thing is HUGE. An even gentler giant than a manatee. 

  These guys went extinct in 1768 due to overhunting. They lived in the cold, shallow waters of the northern part of the Pacific Ocean. Mostly found in the Bering Sea, though said to be on the coasts of Japan and North America before discovery. Adults could be up to 10 meters long. If you’re American and can’t picture in meters, think of an orca, and now think of it even bigger and you get a Steller’s sea cow. They also weight 11 tonnes (~2x heavier than an orca). We don’t know much about this guy, because 27 years after the discovery of the Steller’s sea cow, they went extinct. So we can take what we know about their closest relatives to fill in the gaps. 

We know that they did not have teeth and instead used a hard pad to chew or rip food and had very dense bones to hold them in the water, since they had so much blubber it was doing too good at it’s job and made them more buoyant. The man who discovered the Steller’s sea cow, Steller, describes them as not being able to dive. This is debated, but the advantages of being highly buoyant include using shallow waters to escape predation, minimize heat loss, reduce parasites, and more.

They’ve been described as “walking” on the sea floor and this adaptation can be seen looking at how the fins are positioned to the midline of the creature, instead of outwards like we see in modern day sirenians. 

They were social creatures who lived in large herds who browsed on shallow water floors all day. There is a historic text of a male sea cow ramming and following a boat after they killed a female sea cow. This suggests pair bonds were strong, and that they were monogamous. Unfortunately, living in large groups makes them easy targets for hunters. What’s even sadder is that scientists think when we discovered them, the Steller’s sea cow was already declining and the populations found were remnants of prehistoric herds who managed to survive.

Stuck between the fur trade route for sea otters, the Steller’s sea cow was hunted by fur traders for its meat. It has been said that the sea cow could feed 33 men in a span of a month. Now, we no longer have these magnificent creatures roaming our ocean.

Get the sticker here!

Sources: Patton, J. & Weinstein, B. (2000). “Hydrodamalis gigas” (On-line), Animal Diversity Web. Accessed October 11, 2020 at https://animaldiversity.org/accounts/Hydrodamalis_gigas/

Davis, J. (n.d.). Steller’s sea cow: the first historical extinction of a marine mammal at human hands. The Natural History Museum. https://www.nhm.ac.uk/discover/stellers-sea-cow-first-historical-extinction-of-marine-mammal-at-human-hands.html

[mattyena]

This extinct animal of the week is the Thylacosmilus! This guy was in South America in the Neogene period, just before the Pleistocene (Ice Age) era. Despite its cat-like appearance, this animal is known as the “marsupial saber-tooth.” This is only half right, since the thylacosmilus is actually not a Marsupial, but is in a taxa that is considered the sister of Marsupials, so it’s close enough and is likely nicknamed that due to the familiarity with marsupials. 

During this time, South America actually had many marsupials, so what happened and why are the majority in Australia now? Marsupials originated and were actually plentiful in the land we know as North America. They traveled to South America. Then the marsupials in North America died out. With South America providing new niches, marsupials boomed. But when North America and South America rejoined, the marsupials travelled back to North America, not that successfully though. We can see some relatives like the North American opossum. There are several theories why we don’t see many in North America, but the general theory is that it is too cold for marsupials to diversify there now. South America, Australia, and Antarctica were once connected and it seems like when marsupials reached South America, they travelled further to Australia. Then Australia broke off. There’s a giant gap in the fossil record for Australian marsupials, so it’s unclear why they did well there.

Back to the Thylacosmilus, this guy was about the size of a modern jaguar. The saber teeth are actual an excellent example of convergent evolution. There are two big groups in mammals, the Metatherian (marsupials) and Eutharian (placental) animals. The saber-tooth tiger is a Eutharian mammal and does not share a close lineage to the thylacosmilus. If you remember from my Smilidon #xatw I mentioned how strongly saber-teeth were selected for in the environment. However, the thylacosmilus did not use these teeth for predation. These teeth were actually more triangluar while typical saber teeth were blade-like. The thylacosmilus does not have molars for cutting flesh, but rather for crushing bone. This is puzzling though because it lacks incisors and the wear of the teeth suggest a really soft diet. Some scientists believe the saber teeth were used for cutting the carcass open and eating the insides. The anatomy also suggests they did not pounce on prey, and had a stiff back (oops). This suggests maybe the thylacosmilus was a scavenger? But we have no modern examples of a mammal who has survived purely on scavengering. Maybe we’ll find out one day!

Get the sticker here!

Sources:

Science Laboratory. (2020, June 03). Thylacosmilus Was Not A Saber-Tooth Predator. [Video]. Youtube https://www.youtube.com/watch?v=1wkbzlKn1z8

Geggel, L. (2019, March 03). Why Are There So Many Marsupials In Australia? Live Science. https://www.livescience.com/64897-why-marsupials-in-australia.html

Janis, M.C., Figueirido, B., DeSantis, L. & Lautenschalger, S. (2020, June 26). An eye for a tooth: Thylacsmilus was not a marsupial “saber-tooth predator”. PeerJ.  doi: 10.7717/peerj.9346

Natural History Collections. (n.d.). Origin and Evolution of Marsupials. http://www.nhc.ed.ac.uk/index.php?page=493.168.256

[xatw]

[xatw]

[mattyena]

This extinct animal of the week is the passenger pigeon, which went extinct in 1914. This bird was once very common in the United States, with about 3 - 5 billion individuals in estimate. By 1900, this bird was never to be seen in the wild again, and efforts to breed in captivity failed (every time I write about an extinct species that died out in captivity, it always seems to be in the Cincinnati Zoo, I just thought that was a fun little fact for ya). The male had the striking blue colors, while the female had more dull colors. This is often seen in birds, since males use their colors for display to gain mates. There are a number of hypotheses about the advantage of bright colors. One is that the bright colors indicate the health of a male bird. Another is that the bright feathers are striking to predators, but the bird is alive and strong, indicating it can survive quite efficiently despite the “crutch” of it’s bright feathers. 

This bird was a migratory bird, who likely moved season to season from Ontario to as far as Florida. Their nesting sites were around the Great Lakes to New York. When migrating, they have been recorded to fly 60 mph! These birds were very social, often trees were found to be covered with passenger pigeons in wintering sites.  Despite the pigeon connotation, these birds lived in large hardwood forests. In fact, that led them to their extinction. Deforestation occurred and left them without food or a home. They started eating from the farmland. They became pests and farmers shot them down. Though serious decline occurred when game hunters entered the picture and started selling them for meat in the cities. 

Because they stayed in large flocks, they were easy to pick off. It got to the point where people put hot sulfur under trees so that the birds fall unconscious to the ground where they could kill them. By the late 1800′s it was too late to stop the demise of the passenger pigeon. Legislation introduced did not help their populations.

Their are efforts to introduce the passenger pigeon back into modern day using genetics, similar to how people are attempting to bring the mammoth back, if you remember my first extinct animal of the week. Some argue that the passenger pigeon is what Eastern forests need right now in order to conserve them. Because passenger pigeons had such large flocks, scientists argue that they have sufficient canopy disturbance. What I mean by that is that disturbance in an ecosystem is actually health, allowing for sunlight to hit the ground and stimulate growth, bringing in early succession plants and eventually becoming a closed canopy again. This cycle is health for the ecosystem, of course when not sped up by humans. Scientists believe the passenger pigeon was the main driver for canopy disturbance, and some plants, such as the chestnut tree, have suffered from the lack of passenger pigeons and declining early succession bird species, since some plants require disturbances for their growth. Thus, they argue, by bringing back the passenger pigeon we introduce that dying disturbance back into the ecosystem and make our forests diverse and healthy again. 

Get the sticker here!

Sources:

Department of Vertebrate Zoology of the National Museum of Natural History. (n.d.). The Passenger Pigeon. Smithsonian. https://www.si.edu/spotlight/passenger-pigeon

Revive & Restore. (n.d.). Passenger Pigeon Project. Revive & Restore. https://reviverestore.org/about-the-passenger-pigeon/