Gray Whales Appear to Be Shrinking

Researchers studying gray whales in the Pacific Northwest are worried about an unmistakable trend among the creatures—they're shrinking, and at a pretty fast rate, according to a study published in Global Change Biology.

• Smaller: Whales in this group born after 2000 are about 5 feet, 5 inches shorter than whales born before that date, say researchers in a news release. With a baseline length of about 40 feet, that amounts to a loss of about 13% of their length, or roughly 3 inches per year, reports Scientific American.
• Human comparison: Researchers say that if the same were applied to a female human, she would have shrunk from 5-foot-4 to 4-foot-8.

• The subgroup: The whales studied are in the Pacific Coast Feeding Group, a small subgroup of Pacific gray whales, and they feed off the coasts of Oregon, California, Washington state, and British Columbia. The Washington Post reports that shrinking has been most pronounced in females, which are now generally the same size as the subgroup's males.
• Unclear: Why the whales are getting smaller is unclear. Researchers say it does not appear to be hereditary, thus suggesting environmental factors such as water temperature or changes to their fishing grounds, per the Post.
• Standout quote: "This could be an early warning sign that the abundance of this population is starting to decline, or is not healthy," says co-author KC Bierlich of Oregon State University. "And whales are considered ecosystem sentinels, so if the whale population isn't doing well, that might say a lot about the environment itself."
• Standout quote II: "It is a very surprising finding that it's that dramatic of a change over time," National Oceanic and Atmospheric Administration biologist Aimee Lang tells Scientific American.

(More gray whale stories.)