The walrus, Odobenus rosmarus, is an immense marine mammal of the Arctic, immediately recognizable by its thick body and long ivory tusks. Its size is a consequence of evolution in one of the planet’s harshest environments, leading to a bulk that is difficult to comprehend. This comparison focuses primarily on the Pacific Walrus, the subspecies that achieves the most impressive dimensions, relative to an average adult human.
Specific Dimensions of an Adult Walrus
The Pacific Walrus population, which inhabits the Bering and Chukchi Seas, represents the largest individuals of the species. A fully grown adult male, known as a bull, can weigh up to 1,700 kilograms (3,748 pounds), with some reaching nearly 2,000 kilograms (2 metric tons). This mass is distributed over a body length that typically ranges from 2.7 to 3.6 meters (9 to 12 feet).
Adult females, or cows, are noticeably smaller than males but remain massive animals. A cow can weigh up to 1,250 kilograms (2,756 pounds), often exceeding a ton. Their body length spans between 2.3 and 3.1 meters (7.5 to 10 feet). These measurements establish the walrus as one of the largest pinnipeds, second only to the elephant seal in overall bulk.
Visualizing the Scale
To grasp the scale of a walrus, one must translate its raw weight into relatable human terms. A large male walrus weighing 4,000 pounds is roughly equivalent to the weight of a small four-door sedan or a fully loaded hot tub. Comparing this to the average adult human male weight of approximately 198 pounds, a bull walrus weighs as much as 20 average men standing together.
Standing next to one of these animals would place a 6-foot human at only half the walrus’s 12-foot length. The walrus’s immense girth further emphasizes this difference; its body is cylindrical and extremely thick. A walrus standing on its four flippers would present a wall of muscle and blubber that is significantly wider and taller than a person.
Sexual Dimorphism and Tusk Size
The considerable size difference between male and female walruses is a clear example of sexual dimorphism, with males possessing significantly greater mass and bulk. This size disparity plays a direct role in establishing social dominance and reproductive success among bulls.
The massive canine teeth, or tusks, are a defining feature that both sexes possess, but they are generally longer and stouter on the males. Male tusks can exceed 100 centimeters (39 inches), while female tusks typically reach about 80 centimeters (31.5 inches). A single large tusk can weigh up to 5.4 kilograms (12 pounds). Tusks are used as a status symbol, for fighting rivals, and for hauling the walrus’s tremendous body weight out of the water onto ice floes.
The Biological Reason for Massive Size
The walrus’s massive size is a necessary adaptation for survival in the frigid Arctic environment. A thick layer of blubber, which can measure up to 25.4 centimeters (10 inches) and constitute a third of the animal’s total body mass in winter, is the primary insulator. This dense fat layer traps body heat, making it possible for the walrus to maintain a stable core temperature in near-freezing ocean water.
The large body mass minimizes the surface area-to-volume ratio, which further reduces heat loss. This bulk also serves as a crucial energy reserve, allowing the animal to survive long periods of fasting when food is scarce. The physiological capacity to carry this mass supports their diving behavior, as the body stores oxygen more efficiently in blood and muscle tissue to sustain foraging trips to the ocean floor.