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A pair of horns on a male impala Anatomy of an animal's horn. A horn is a permanent pointed projection on the head of various animals that consists of a covering of keratin and other proteins surrounding a core of live bone. Horns are distinct from antlers, which are not permanent.
Antlers are considered one of the most exaggerated cases of male secondary sexual traits in the animal kingdom, [10] and grow faster than any other mammal bone. [11] Growth occurs at the tip, and is initially cartilage, which is later replaced by bone tissue. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies.
During the Pleistocene epoch, about 11 other antilocaprid species existed in North America, many with long or spectacularly-twisted horns. [8] Three other genera (Capromeryx, [9] [10] Stockoceros [11] [12] and Tetrameryx [13]) existed when humans entered North America but are now extinct. The pronghorn's closest living relatives are the giraffe ...
The primary difference between antlers and horns is that the former are seasonal while the latter are permanent. Antlers are the fastest-growing tissue on the planet, expanding at a rate of up to ...
The first regular steamship service from the west to the east coast of the United States began on February 28, 1849, with the arrival of the SS California in San Francisco Bay. California left New York Harbor on October 6, 1848, rounded Cape Horn at the tip of South America , and arrived at San Francisco, California after a 4-month 21-day journey.
The American frontier, also known as the Old West, and popularly known as the Wild West, encompasses the geography, history, folklore, and culture associated with the forward wave of American expansion in mainland North America that began with European colonial settlements in the early 17th century and ended with the admission of the last few ...
True horns are found mainly among: Ruminant artiodactyls. Antilocapridae ; Bovidae (cattle, goats, antelopes etc.). Giraffidae: Giraffids have a pair of skin covered bony bumps on their heads, called ossicones. Cervidae: Most deer have antlers, which are not true horns due to lacking a bone core and made of keratin.
Pronghorns are similar to horns in that they have keratinous sheaths covering permanent bone cores; however, these sheaths are deciduous and can be shed like antlers. [4] Very little is known about the development of pronghorns, but they are generally presumed to have evolved independently. [ 4 ]