MAMMOTHS AND ELEPHANTS

Family Elephantine = mammoths and elephants. Elephants today are represented by two genera/species: Loxodonta africana = the African elephant, and Elephas maximus = Indian or Asian elephant. Both of these genera range in geologic time from the late Miocene to Recent. 

Elephants are the largest living terrestrial mammals.

Their dental formula is 1/0, 0/0, 3/3, 3/3 = 26.

The six cheek teeth are replaced continuously from the rear throughout life; but they are only six replacements in the lifetime of about 50 years for an elephant. Only one (or one and part of another) cheek tooth is functional at a time. Each tooth is shed as it becomes worn.

They have no canines, and their tusks are incisors:

Loxodonta africana = African elephant has a pair of upper incisors elongated into tusks reaching over 3 m long in males.

 

Female Elephas maximus usually have no incisors, thus they have no tusks.

Early mammoths apparently evolved from gomphotheres (see one of my previous posts) in Europe during Miocene time. The fossil record of mammoths is imperfect, but they continued to be present in Europe during the Pliocene and Pleistocene.

Most mammoths belong to genus Mammuthus. Mammuthus meridonalis migrated out of Africa at the beginning of Pliocene time, about 5 mya. It traveled into Europe and then crossed the Beringia Land Bridge 3 into North America during the Pleistocene (see one of my earlier posts on fossil mammals). It eventually reached the west coast of the United States later during the Pleistocene. 

The biggest mammoth was the Europe/Asia Pleistocene Mammuthus trogontherii, which was about 15 feet high at the shoulder and had tusks up to 16.5 m long. [It evolved from Mammathus meridionalis.] Mammuthus trogontheril then migrated to North America (also via Beringia Land Bridge 3) and evolved into Mammuthus columbi. A rather famous locality for the remains of M. columbi is near Hot Springs, South Dakota. Apparently, an ancient sinkhole in this area “lured” many young mammoths to their death 26,000 years ago.

                 Literature research and drafting for this diagram by R. Squires 2022

Mammuthus exilis was a pygmy mammoth (only 4.5 to 7 ft. tall and 2000 pounds compared to its direct ancestor: the 14 ft. tall and 20,000 pound M. columbi) found on the Channel Islands (primarily Santa Rosa Island) off the coast near Los Angeles. The predecessor of M. exilis reached the islands 40,000 years ago by means of swimming (i.e., sea level was 300 ft. lower than today and the island was only 6 miles from the mainland. They evolved from normal-size M. columbi mammoths, but migrated to the islands because of increasing scarcity of food, increasing competition with other animals, and, most likely by predation from cats and wolves.

One of the more famous mammoths in the North American Pleistocene rock record is Mammuthus columbi [also known as M. imperator (the "Imperial" Mammoth) or, according to some experts, as Mammuthus meridionalis]. It is best known from the La Brea Tar Pits at Los Angeles, southern California. This mammoth reached a maximum height of 13 feet (3.9 m). The average adult size was 12 feet (3.6 m) tall and was about 10,000 pounds (4,900 kilograms). 

On the left is Mammuthus columbi from the La Brea Tar Pits. On the right is a mastodon, also from the La Brea Tar Pits (see my previous post). 

Three views of Mammuthus columbi: upper image shows most of the skeleton, middle image shows the right side of the skull (including jaw bone and a molar); lower image shows the molar tooth more clearly. This skeleton of the late Pleistocene Mammuthus columbi [formerly known as M. imperator = Imperial Mammoth] is on display to the public at the La Brea Tar Pits Museum in the Los Angeles area of Southern California. 

Replica (cast) of a single molar tooth (2 in wide x 1 3/8 in high) from a Pleistocene juvenile mammoth. Mammoth molars have a flat chewing surface (in comparison to mastodons) because mammoths ate grasses.

The so-called "wooly mammoth" = Mammuthus primigenius (shown below) is also of late Pleistocene in age [to no younger than 10,000 years ago]. It was widespread  throughout the Arctic tundra-vegetation zone, in both the New World and Old World. It too migrated via Beringia 3 from Europe to North America (actually during the last Ice Age).

A plastic model of Mammuthus primigenius.

References Used:

Jefferson, G.T. and L. Lindsay. 2006 Fossil treasures of the Anza-Borrego Desert. The  last seven million years. Sunbelt Publications. 394 pp.

Savage, R.J.C. and M.R. Long. 1986. Mammal evoution an illustrated guide. British Museum (Natural History). 299 pp.

www.nps.gov  Channel Islands pygmy mammoths (this site has several interesting videos about these mammoths.)