Mammals

Lat: 47.65520606989774, Lon: -122.30810444799601
Day, 2012
5/15/12
1:30-3:30

Today we had a guest lecture by Jim Kanagy. He is the curator of mammals at the Burke Museum. Jim told us that mammals and birds have only been here for the last 60 million years or so, so they are a relatively young species. Of all the vertebrates, mammals make up only 1/16 -1/8 of them, while fish make up about half. There are 29 orders and about 5,400 species.

Some of the general characteristics of mammals are that they have fur, produce milk, they have one single lower jaw bone, three middle ear bones. All mammals (humans included) have the same set of bones; they just differ in form and location. Some of this diversification is due to differences in diet which can affect the shape and structure of the skull, where the teeth are placed and how many there are, etc.

One thing I found really interesting was that rodents and bats make up almost 2/3 of all mammals. There are 2,277 rodentia (rodent) species and 1,186 chiroptera (bat) species. Carnivores only have 286 species which is considerably smaller in comparison. The reason for such great success of the rodents is that they are generalized creatures, which means there are a lot of very similar species.

Another fact is that Washington State only has 9 of the 29 orders of mammals. This doesn’t seem like a whole lot but when you consider the fact that the Pacific Coast is so diverse and contains so many different habitats and topographies, 9 orders may actually be a lot. The state has carnivore, artiodactyla, rodentia, lagomorph, chiropetra, soricomporpha, primates, didelphimorphia, and catacea. The interesting part is that about 10,000 years ago we used to have a lot more orders and species. We used to have perissodactyla (horses, rhinos…), proboscidea (elephants), cingulate (armadillos), pilosa (sloths, anteaters), and sirenia (manatees, dugongs). This makes me wonder why these orders are no longer seen here; did they become extinct, did humans overhunt them, did they just move, or did climate change affect their habitat so they could no longer live hear?

Posted on June 1, 2012 10:45 PM by lisad22