{"id":1871,"date":"2023-04-21T23:00:00","date_gmt":"2023-04-21T23:00:00","guid":{"rendered":"https:\/\/live-usc-dornsife.pantheonsite.io\/wrigley\/?p=1871"},"modified":"2025-10-09T22:47:17","modified_gmt":"2025-10-09T22:47:17","slug":"usc-natural-history-museum-collaboration-channel-island-fox-conservation-research","status":"publish","type":"post","link":"https:\/\/dornsife.usc.edu\/wrigley\/2023\/04\/21\/usc-natural-history-museum-collaboration-channel-island-fox-conservation-research\/","title":{"rendered":"USC, Natural History Museum collaborate to ensure long-term survival of Channel Island fox"},"content":{"rendered":"\n\n\n\n\n \n \n\n\n\n\n\n\n\n
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USC, Natural History Museum collaborate to ensure long-term survival of Channel Island fox<\/h1>\n\n\n<\/div>\n \n \n By<\/span>Kathryn Royster<\/strong>\n \n April 21, 2023<\/span>\n <\/div>\n<\/div>\n\n\n <\/div><\/div>\n\n \n \n\n\n\n\n\n\n\n
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Today, 22 miles of water separate Santa Rosa Island (one of six large Channel Islands) from mainland Southern California. But 20,000 years ago, the distance was much shorter. An ice age had sucked up much of the ocean\u2019s water into a massive ice sheet on the northern continents, causing a drop of sea levels of about 400 feet, and only about 5 miles of water separated the land masses on either side of what is now the Santa Barbara Channel.<\/p>\n

Five miles happens to be a very reasonable distance for elephants to swim \u2013 which, according to Natural History Museum of Los Angeles (NHMLA) Curator and Chair of Vertebrate Paleontology\u00a0Xiaoming Wang<\/a>, is why Santa Rosa is littered with mammoth fossils. The animals likely swam to Santa Rosa at some point during the ice age, and conditions on the island were favorable enough that they stayed. The fossils from Santa Rosa, however, highlight an interesting twist to the story: the swimming mammoths\u2019 descendants gradually shrank in size and became a new species. Santa Rosa\u2019s dwarf\u00a0Mammuthus exilis<\/i>\u00a0(literally, \u201cexiled mammoth\u201d) was only 5-6 feet tall, about half the height of its mainland ancestors.<\/p>\n

\"\"
Xiaoming Wang in the fossil storage room of the Natural History Museum of Los Angeles. The fossils in the drawers are from dwarf mammoths that once lived on Santa Rosa Island, off the coast of California. (Nick Neumann\/USC Wrigley Institute)<\/figcaption><\/figure>\n

Wang has studied\u00a0Mammuthus exilis<\/i>\u00a0extensively, and he says the animal\u2019s story is a prime example of what scientists call the \u201cisland effect\u201d or \u201cisland rule\u201d: \u201cIf an animal that comes to an island is roughly larger than a breadbox, their descendants tend to shrink their body size because the island resources are limited compared to the mainland. This happened with the island mammoths over a fairly fast span of time,\u201d Wang says.<\/p>\n

Island rule, island fox<\/h4>\n

Santa Rosa\u2019s mammoths died out at the end of the ice age about 11,000 years ago, but that island and the five other large channel islands are now home to another animal that evolved under the island rule: the Channel Island fox (Urocyon littoralis<\/i>), a smaller relative of the mainland gray fox (Urocyon cinereoargenteus<\/i>). Wang is a specialist in the evolution of fossil canids (dog-like carnivores, including foxes), and with the support of the USC Wrigley Institute for Environment and Sustainability, he and USC Dornsife Professor of Biological Sciences\u00a0Suzanne Edmands<\/a> (left) have been working together for almost 15 years to uncover clues to the evolutionary history of and effective conservation strategies for the little fox. \"\"<\/p>\n

Their collaboration is unusual because, while Edmands focuses on conservation genetics, Wang focuses on morphology (body shape and size). The two disciplines don\u2019t typically work together, which means that researchers like Edmands often don\u2019t know how the genes they\u2019re studying relate to animals\u2019 evolutionary adaptations, and researchers like Wang often aren\u2019t aware of the molecular or genetic mechanisms that affect morphology. The two scientists want to bridge those gaps because they believe that, in doing so, they\u2019ll have a better shot at supporting conservation and management of what Edmands calls \u201ca very unique and threatened species.\u201d<\/p>\n

The Channel Island fox is in a perilous position due to an outbreak of canine distemper and increased predation by golden eagles in the 1990s. These pressures brought the species to the brink of extinction, but thanks to intensive conservation work, it has since been upgraded to \u201cnear threatened\u201d status. Because the current population was rebuilt from very low numbers, however, the foxes currently living on the Channel Islands have very low genetic diversity. This makes them potentially more vulnerable to threats such as disease, physical weakness or deformities, and environmental changes.<\/p>\n

There is some good news, however. In the first phase of their research, Wang, Edmands, and then-USC Dornsife Ph.D. student Nicole Adams \u201819 dug deeper into the molecular side of things. They used tissue samples from the NHMLA\u2019s collection and fox feces collected in the wild to study the bacteria in the fox\u2019s gut (its microbiome) and the portion of its genes that are actually expressed (its exome). They found that, although exome diversity in the fox population is low and has declined further since the 1990s, the animals have reasonably good diversity in their gut microbiome.<\/p>\n

\u201cThe gut microbiome is super important in immunity and general health. It could be an alternate way for the foxes to deal with environmental changes,\u201d Edmands says.<\/p>\n

Finding the origin(s) of a species<\/h4>\n

In the current research phase, Edmands and Wang are working with USC Dornsife marine and environmental biology Ph.D. student\u00a0Kimberly Schoenberger<\/a>\u00a0(right) to investigate how the fox may have ended up on the Channel Islands in the first place. Based on the fossil record, scientists believe that mainland gray foxes first came to the northern Channel Islands 6-8,000 years ago and later reached the southern islands as well. Unlike the mammoths, the smaller foxes would have been unlikely to swim the channel, which grew wider after the ice age ended. Wang says, however, that the foxes could have \u201crafted\u201d over by clinging to pieces of wood or other floating objects. They might also have arrived with Indigenous people, who developed thriving settlements in the Channel Islands during that period.<\/p>\n

\"\"<\/p>\n

Working with NHMLA specimens, Schoenberger is comparing morphological differences between mainland gray foxes and island foxes. She uses a specialized data visualization program to create 3D models of the two species\u2019 skulls from CT scans, then takes measurements of interior and exterior dimensions. Because mammals\u2019 brains generally grow to completely fill the insides of their skulls, she can use the interior space captured in the scans to generate a model of the brains, which are not preserved in historic samples. These \u201cendocasts\u201d can be used to both examine the shape of the brain and to determine how large the two species\u2019 brains are in comparison to their overall body sizes.<\/p>\n

\u201cThrough either domestication or adaptation to island life, larger mammals often develop a smaller brain size because the brain is a very resource-heavy organ, and there has to be a reason to maintain it,\u201d Schoenberger says. \u201cIf the animal doesn\u2019t need that same cognitive capacity to evade predators or hunt for prey, they might evolve a smaller brain size compared to the rest of their body. By comparing how brain size changed as the island fox evolved, we can infer a lot of additional information about how and why that might have happened.\u201d<\/p>\n

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