Extinct goat was cold-blooded (2009)

We still have one cold-blooded mammal species around[1]. And a few marine fish species that are partially[2] or fully warm-blooded[3].<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Naked_mole-rat" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Naked_mole-rat</a><p>[2] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Swordfish" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Swordfish</a><p>[3] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Thunnus" rel="nofollow noreferrer">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Thunnus</a>

Some days ago there was news about some researchers predicting mammals would be doomed by the next supercontinent cycle, due to too high temperatures incompatible with warm blooded creatures. Well, if mammals can just evolve back cold blood, perhaps that makes their thesis moot. See <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=37654289">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=37654289</a>

There are bison on Catalina Island, left there by a film company around a hundred years ago. They are smaller than bison on the mainland:<p><i>“They’re very challenged healthwise when they’re on this island because they don’t have the adequate nutrition during the right time of year,” King said. “So, our bison are in fact a little smaller than the mainland, and it’s not a genetic difference. It’s due to not having the right nutrients at the right time.”</i><p><a href="https:&#x2F;&#x2F;www.voanews.com&#x2F;a&#x2F;history-catalina-bison-hollywood-tourism-ecology&#x2F;3930517.html" rel="nofollow noreferrer">https:&#x2F;&#x2F;www.voanews.com&#x2F;a&#x2F;history-catalina-bison-hollywood-t...</a><p>The article also notes that bison from the island were relocated back to the mainland on three separate occasions to try to reestablish herds here. I can&#x27;t currently find a citation, but I recall reading that bison that were returned to the mainland put on weight.<p>It&#x27;s well established that island populations of animals trend physically smaller. That part isn&#x27;t at all news.

Just because their bones grew in cycles like reptiles, does that necessarily mean they have to be cold-blooded too?

It became extent only 3,000 years ago?! Can we assemble a genome?!

No such thing as hot or cold blooded.<p>You have:<p><pre><code> Endothermic: Generating internal heat to moderate body temperature, e.g., modern birds and mammals. Ectothermic: Relying on the environment and behavior to regulate body temperature, e.g., typical reptiles. Homeothermic: Maintaining a constant internal body temperature, e.g., modern mammals, birds, and some others. Poikilothermic: Having a fluctuating internal body temperature depending on the local environmental conditions, e.g., typical reptiles and actinopterygiian fish.</code></pre>

Huh. Is the evidence mostly bone growth patterns? That certainly seems likely to follow metabolism... but it does make me wonder what the difference is compared to hibernating mammals. (Much) longer periods at each rate? Something else?

Bears, and some other mammals, hibernate during which their metabolism drops. Any reason to believe this isn&#x27;t just an exaggeration of that? It just seems really hard to believe actual cold bloodedness could appear like that. Why wouldn&#x27;t lizards colonize the island instead?

&gt; Myotragus survived on the island as dwarf cold-blooded animals for millenia because they had no natural enemies, but they could not survive the predation of humans when they arrived on the island about 3,000 years ago.<p>One more thing killed by humans.

Very unlikely. needs better proofs<p>... and they need also to review the concept of fibrocartilage, that shows very similar rings, in animals not suspicious at all of having a reptilian metabolism or cold blood (Like, for example: humans).<p>The main problem could be trying too hard to milk a poor sample. If this animal was cold blooded, why the other goats and sheep living in bad places didn&#x27;t developed a similar system? We have lots of sheep races selected for very poor environments. We fully explored their different genetic possibilities... nobody has seen a &quot;crocodile like&quot; sheep in the whole planet

&gt; The bones of warm-blooded animals show uninterrupted fast growth, while the bones of cold-blooded animals have parallel growth lines showing interrupted growth corresponding to growth cycles, rather like the rings seen in tree trunks. Growth and metabolism rates are adjusted to suit the amount of food available, whereas warm-blooded animals require food to be available continuously. The Myotragus bones showed the same interrupted growth as reptiles.<p>Or the goat skeletons had regular periods of interrrupted food leading to regular harsh starvations which left patterns on the bones, maybe?

Kind of a crossover thing from the blind cooking post, but it&#x27;s interesting that they have smaller eyes and smaller brains.<p>Basically, if you assume that vision requires a lot of compute power to process, and that compute power (that is, brains) are major energy users, those with simpler vision processing needs use less energy.<p>It&#x27;s kind of a first principles thing I suppose. What uses a lot of energy? Brain. What is the brain doing a lot? Managing vision. Idea? Reduce vision input.

Wow - mind blown. I had somehow assumed large creatures can&#x27;t be cold-blooded

Imagine have a tiny, lazy goat for a pet.

&quot;Myotragus balearicus&quot; would be a good black metal band name now. The cold-blooded goat.

(2009)