Nav: Home

In polar regions, warm-blooded marine predators rule

January 24, 2019

Even though diversity typically decreases from the tropics to the poles, in the frigid waters of the high latitudes, warm-blooded marine mammals and birds thrive, both in number and species richness. The findings of a new related study help to explain a long-standing ecological paradox: Why does the biodiversity pattern of marine mammals and birds - which exhibits greater species richness at the poles than in the tropics - deviate from that of most other life on Earth? What's more, the results highlight new challenges that animals like whales, seals and penguins will likely face as polar sea temperatures continue to rise. Most of the planet's biodiversity is concentrated near the tropics and forms a well-documented latitudinal gradient of increasing diversity toward the equator. This diversity gradient is a pattern widely observed in nearly every form of animal, plant and insect life on the land and in the oceans. However, for marine mammals and birds, the polar opposite is true. The tropics are home to very few warm-blooded mammals and bird species, like seals, whales and penguins, and only dolphins show high diversity in the warmer waters of tropical seas, according to the authors. Why this group of animals exhibits such a different pattern of diversity has remained unknown. To address this puzzle, John Grady and colleagues compiled a distributional database of 998 top marine predators, including whales, sharks, fishes, seabirds and reptiles, which revealed striking differences in the biogeography of both warm- (endothermic) and cold-blooded (ectothermic) predators. Grady et al. then modeled predation rates, metabolism and water temperature among these species and found that, overall, warm-bodied predators are favored where prey are "slow, stupid and cold." They have a metabolic advantage when it comes to hunting prey in these conditions - becoming faster than their cold-blooded counterparts, as water temperatures decrease. Their metabolism allows them to generate heat to elevate temperatures in the eyes and brain in some cases, to improve sensory abilities as they hunt. In a related Perspective, Nicholas Pyenson discusses the study in more detail.
-end-


American Association for the Advancement of Science

Related Biodiversity Articles:

Biodiversity is 3-D
The species-area relationship (SAC) is a long-time considered pattern in ecology and is discussed in most of academic Ecology books.
Thought Antarctica's biodiversity was doing well? Think again
Antarctica and the Southern Ocean are not in better environmental shape than the rest of the world.
Antarctica's biodiversity is under threat
A unique international study has debunked the popular view that Antarctica and the Southern Ocean are in much better ecological shape than the rest of the world.
Poor outlook for biodiversity in Antarctica
The popular view that Antarctica and the Southern Ocean are in a much better environmental shape than the rest of the world has been brought into question in a study publishing on March 28 in the open access journal PLOS Biology, by an international team lead by Steven L.
Temperature drives biodiversity
Why is the diversity of animals and plants so unevenly distributed on our planet?
More Biodiversity News and Biodiversity Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Teaching For Better Humans
More than test scores or good grades — what do kids need to prepare them for the future? This hour, guest host Manoush Zomorodi and TED speakers explore how to help children grow into better humans, in and out of the classroom. Guests include educators Olympia Della Flora and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...