Ivory is a hard, white material primarily originating from the teeth and tusks of certain animals. Valued for centuries for its beauty and durability, ivory is commonly associated with elephants but is also found in other species. It serves diverse and important functions in their natural lives.
Defining Ivory Tusks
A tusk is an elongated, continuously growing tooth that extends beyond an animal’s mouth. These specialized teeth are typically either incisors, as seen in elephants, or canines, such as those found in walruses and hippopotamuses. Ivory is primarily composed of dentin, a calcified tissue distinct from bone or horn. Dentin is a dense, bony tissue, which is covered by a thin layer of cementum, and in some areas, enamel. Tusks differ from horns, which grow from an animal’s head and consist of a bony core covered in keratin. Unlike horns, tusks are teeth, growing from the jaw, and continue to develop throughout the animal’s life.
Key Animals with Ivory Tusks
Elephants are the most recognized animals with ivory tusks. Both male and female African elephants typically possess tusks, which are elongated incisor teeth that grow throughout their lives. African elephant tusks average about 6 feet (2 meters) in length and can weigh around 50 pounds (23 kg) each, though some can reach up to 11.5 feet (3.5 meters) and weigh almost 265 pounds (120 kg). Asian elephants, by contrast, usually only have prominent tusks in males, while females often have small or no tusks.
Walruses also possess prominent ivory tusks, which are elongated upper canine teeth. Both male and female walruses have these tusks, though male tusks tend to be longer, straighter, and stouter, growing up to 3 feet (1 meter) in length. Narwhals, often called “unicorns of the sea,” are unique for their single, spiraled tusk, which is an elongated left canine tooth that can reach up to 10 feet (3 meters) long. While primarily found in males, females rarely grow smaller tusks.
Hippopotamuses also have large canine teeth that are considered ivory, with the lower canines reaching up to 20 inches (50 cm) in length. These teeth grow continuously and are significant in size, particularly in males. Beyond living species, extinct animals like mammoths and mastodons were well-known for their massive, curved tusks, which were also made of ivory.
Purpose of Tusks in Animals
Tusks serve a variety of important biological and behavioral functions for the animals that possess them. For elephants, tusks are versatile tools used for foraging, such as digging for roots, water, or minerals in dry riverbeds. They also aid in stripping bark from trees for food and can be used to lift or move objects. Tusks provide defense against predators and rivals, and male elephants use them in displays of dominance during mating season.
Walruses rely on their tusks for navigating their icy habitats and for social interactions. They use them to haul their massive bodies out of the water onto ice floes or rocky shores, acting as natural ice picks. Tusks also help walruses create and maintain breathing holes in thick ice, allowing them access to air while foraging underwater. In social contexts, tusks are displayed to establish dominance, and males use them when competing for mates.
Narwhal tusks, while primarily considered secondary sexual characteristics for display and social status, also have practical uses. Their tusks are highly innervated sensory organs with millions of nerve endings, allowing them to sense changes in water temperature and salinity. Narwhals have also been observed using their tusks to stun prey, like small Arctic cod, making them easier to catch. Hippopotamuses primarily use their large canine tusks for combat, often in aggressive displays or fights over territory and mates.