Marine Animals: Gray Whales

Gray whales are some of the greatest travelers in the oceans. Each year, gray whales migrate from North Pacific waters to equatorial waters off the coast of Mexico, a journey of over 10,000 miles that begins in the fall. The whales spend the winter months in warm waters where they breed before returning north in May. The gestation period of gray whales is around 12 months; mothers give birth every two to three years to a single calf, usually between fourteen and sixteen feet long and weighing as much as 2000 pounds. Gray whales can grow to lengths of 50 feet, weighting up to 90,000 pounds. They have a hump on their back, followed by a series of small bumps or knuckles along a ridge on their dorsal side. Their tail fins can be 10 feet wide, with a deep notch in the middle.

Grey Whale distribution. Image from NOAA,

Gray Whales were called “friendly whales” in the seventies because of their curiosity and willingness to approach small boats. Their congeniality and curiosity may have put them at risk, as they were nearly hunted to extinction by commercial whaling in the 20th century. The Endangered Species Act of 1973 offered protections to the Gray Whale, and by 1994 the eastern North Pacific population of Gray Whales was determined to have successfully recovered. The western population of Gray Whales remains below 200 individuals today. Today, the greatest threats to Gray Whales include entanglement in fishing gear, collisions with ships, and noise pollution. Noise from ships and other activities confuses Gray Whales and can alter their migration patterns, or even cause strandings on beaches. Additionally, shifts in temperature due to climate change and overfishing are forcing whales to travel farther to find food.

This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to and click On the Ocean.

Script Authors: Kelsey Gibbons and Kayla Ponder

Editor: James M. Fiorendino

Contributing Professor: Dr. Lisa Campbell

Cover Image: NOAA,