• chevron_right

      By learning to hunt otters, wolves decimate a deer population

      news.movim.eu / ArsTechnica · Thursday, 26 January, 2023 - 15:15 · 1 minute

    Image of a sea otter floating with its pup.

    Enlarge / So cute yet—for some animals—so tasty. (credit: Arthur Morris )

    People love otters, wolves, and deer. Respectively, they’re crafty, intelligent, and majestic. Put them all together on an island, though, and things get unpleasant pretty quickly. These are the findings of a new paper analyzing how a wolf population came to Pleasant Island in Alaska, learned to hunt otters, and, using this unexpected food source, thrived to the point of wiping out the native Sitka black-tailed deer population.

    “To the best of our knowledge, the deer population is decimated. We haven't found evidence of deer recolonizing the islands,” Gretchen Roffler, wildlife research biologist for the Alaska Department of Fish and Game and an author of the paper, told Ars.

    Deer diary

    The deer have been on Pleasant Island for a long time. The sea otters had also been in the waters off the coast of Alaska until the fur trade killed most of them off by the late 1800s or early 1900s, Roffler said. However, the otters were declared an endangered species, and a population was reintroduced to the area in the 1960s . In the 1980s , they moved into the waters near Pleasant Island and continued to propagate.

    Read 14 remaining paragraphs | Comments

    • chevron_right

      Behavior-changing parasite moves wolves to the head of the pack

      news.movim.eu / ArsTechnica · Tuesday, 29 November, 2022 - 18:14

    An image of 3 wolves in a snowy landscape.

    Enlarge (credit: Russell Burden )

    Toxoplasma gondii is a ubiquitous protozoan parasite that can infect any warm-blooded species. In lab studies, infection with T. gondii has been shown to increase dopamine and testosterone levels along with risk-taking behaviors in hosts including rodents, chimps, and hyenas. Oh, and humans.

    But its effects have not really been studied in the wild, so some researchers decided to assess how infection impacts gray wolves in Yellowstone National Park. They found that “the odds that a seropositive [infected] wolf becomes a pack leader is more than 46 times higher than a seronegative wolf becoming a pack leader.”

    In the wild

    Serum samples have been taken from the wolf packs in Yellowstone since 1995. These scientists assayed samples from 229 individual wolves taken over the years—116 males, 112 females, and one hermaphrodite—to try to correlate the presence of antibodies against the parasite with demographic factors and specific behaviors. (The relationship between antibodies and infection is complicated, given that the parasite can persist at low levels indefinitely after infections.)

    Read 6 remaining paragraphs | Comments

    • chevron_right

      Ancient wolf genomes indicate an East Asian origin for dogs

      news.movim.eu / ArsTechnica · Wednesday, 29 June, 2022 - 23:43 · 1 minute

    Image of a single wolf.

    Enlarge / An Eastern Gray Wolf is a mix of Siberian ancestry and coyote DNA. (credit: Michael Cummings )

    Man's best friend was the first of many animals humans have domesticated. But there was no clear before-and-after moment where dogs were suddenly a distinct population of wolves. While some ancient skeletons are clearly dogs, there are a lot of ambiguous skeletons earlier than that. It's possible to get a sense of what happened using the genomes of modern and ancient dogs. But this analysis depends heavily on what you think the wolf populations dogs were derived from look like.

    Now, researchers have generated a much clearer picture of the last 100,000 years of wolf evolution. The picture it paints is a population that remained a single unit despite being spread across continents in the Arctic, with the population sporadically refreshed from a core centered in Siberia. Many breeds of dogs seem to have been derived from a population of East Asian wolves. But others seem to have also received significant input from a Middle East population—but it's unclear whether that population was wolves or dogs.

    Wolves around the north

    The ability to sequence ancient DNA was essential to this new work, which involved obtaining DNA from 66 wolf skeletons that collectively span about 100,000 years of evolution, including most of the last ice age. Wolves are found in the Northern Hemisphere, and the skeletons used here tend to be closer to the Arctic (probably in part because DNA survives better in cooler climes). But they are widely distributed, with Europe, Asia, and North America represented. The researchers also included five ancient wolf genomes that others had analyzed, along with some genomes of modern wolves.

    Read 10 remaining paragraphs | Comments

    index?i=DU7vRQHATPI:kNs04v6fdvc:V_sGLiPBpWU index?i=DU7vRQHATPI:kNs04v6fdvc:F7zBnMyn0Lo index?d=qj6IDK7rITs index?d=yIl2AUoC8zA