STL Science Center

STL Science Center

11 August 2018

New Week

I intended to discuss the book Unnatural Selection more than I was able to last week, but I received an email that has kept me fairly bust since last Monday or Tuesday. Instead of spending multiple weeks on the book, I thought that this week we could di○scuss a fossil ancestor of one of the animals that is highly important to discussions in the book about selective breeding. We have discussed the origins of cats and dogs a number of times here and we have also discussed more than a few early birds, their cousins, and their ancestors. The remaining group that I had mentioned from the book is that lovable farm (and table group), the pigs (a magical animal, as regards the table comment).

Suidae consists of a large group of animals, both domesticated and feral, today. At one point we tried to discuss the origin of pigs, but they are a diverse group of animals that have evolved into 17 species across 6 genera and a wide variety of sizes and diets. Also, it was a two entry week, because I was extremely busy, in which we discussed Strozzi's Pig (Sus strozzi). The story of the evolution of the domesticated pig begins with the wild boar (Sus scrofa) and Strozzi's pig is a step along the road between ancient relative and modern pigs. Part of the reason Strozzi's pig died out is actually tied to surges in the population of S. scrofa. Going farther back on the family tree is somewhat problematic, but entertaining because the clade that all pigs and boars belong to is called Artiofabula which welcomes its own puns. Despite all we know about living pigs and boars and having a general idea about their familial relationships, there is not that much known about the origins of Suiidae itself. However, because we had a brief discussion about S. scrofa and domestication before, we are going to talk this week about an ancestor of the peccaries, rather than the wild boar.

Peccaries of the family Tayassuidae in the group of Suidae are the only pigs native to the Americas. Historically measuring approximately 90 and 130 cm (3.0 and 4.3 ft) in length and about 20 to 40 kg (44 to 88 lb), peccaries are smaller than boars and domesticated pigs. Wild pigs and boars in the United States, for instance, are not peccaries but feral versions of the domesticated pigs that came over with European settlers. One of the most well-known wild suids in the United States, the javelina, is a peccary though. Confusion between feral domesticated pigs and peccaries is very common. Regardless, peccaries have their own rich history in North America. One of the extinct members of the family, Platygonus, consists of 18 described species of ranging from Canada to Mexico and California to Pennsylvania throughout the Pliocene and into the Pleistocene. Platygonus was rather large for a peccary at 1 m (3.3 ft) long. Long legs made it capable of running at a fair speed and tusks allowed it to defend itself from predators. It is thought that these peccaries lived in herds as well, making them a bit more well protected than solitary pig and peccary species.

©Charles R. Knight, Platygonus leptorhinus

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