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The Endemic Species of Channel Islands

What is an endemic species?

"Endemic species are plants and animals that exist only in one geographic region. Usually an area that contains endemic species is isolated in some way, so that species have difficulty spreading to other areas, or it has unusual environmental characteristics to which endemic species are uniquely adapted."

Millions of years ago, the Channel Islands were one super island called Santarosae. This island was six miles off the coast of California. Over time and ice ages, the super island broke up into smaller islands, as we know them today.

The 6-mile separation from the mainland allowed animals to swim across easily enough, but when the island broke apart and drifted further into sea, those species became more and more isolated. When a localized species remains isolated for a long amount of time, environmental and genetic factors can result in a new species. On the Channel Islands, 137 of the 621 (22%) species of plants and animals are endemic.

For example, the torrey pines found on Santa Rosa Island were once found all along coastal California, when the climate was cooler and moister. Over time, as the climate became warmer and drier, Torrey pines became restricted to two locations, along the coast of Santa Rosa and Torrey Pine State Reserve in San Diego County where the climate is cool and foggy.

Another notable (and adorable) endemic species is the island fox. They are found on six of the eight Channel Islands, and each island population is considered it's own unique endemic subspecies. It is the only carnivore that is unique to California, and is about 1/3 the size of their ancestor, the grey fox, making them the size of a house cat. Since they have evolved in isolation, with no natural predators, they hunt during the day, compared to their ancestor the grey fox, which hunts at night, so they are very common to see on the Channel Islands. (And also very used to humans, forcing the park to implement "fox boxes" for visitors to keep their food and cookware.)

The island scrub-jay is only found on Santa Cruz island, making it the bird with the smallest range of any bird species in North America. Compared to its cousin the California scrub-jay, found on the mainland, the island scrub-jay is darker blue and larger (which is interesting because the isolation has made most endemic species smaller). People will travel to Santa Cruz island from all over the world to get a glimpse of this unique and rare bird.

Other endemic species on the Channel Islands include the island spotted skunk (found on Santa Cruz and Santa Rosa), island deer mouse (a different species is found on each of the islands), and Santa Cruz island gopher snake (you guessed it, found on Santa Cruz).

Perhaps most fascinating is the discovery of the pygmy mammoth on the Channel Islands.

In 1873 there were reports of "elephants" on Santa Rosa. Later these claims were classified as Columbian mammoths, in which fossils had been found on the mainland. These Columbian mammoths could stand up to 14 feet tall and weigh up to 20,000 pounds.

Then, in 1927, a new species of mammoth was discovered, named the Mammothus exilis, and would have varied from 4.5 feet to 7 feet and weighed up to 2,000 pounds, making it approximately the same size as a bison. Because of their isolation from the mainland, it is thought that the population of Columbian mammoths became smaller over time, due to scarce food supply, climate changes and lack of predation, creating a new species that is only found on the Channel Islands.

Pygmy mammoth remains have been found most frequently on San Miguel and Santa Rosa islands.

In 1994, the world's first virtually intact pygmy mammoth skeleton was found on Santa Rosa.

Over the past 40 years, the National Park Service has invested over $20 million in protecting the native and endemic species of the Channel Islands by removing invasive non-native species, including rats, cats, feral pigs, deer, elk, golden eagles and a variety of weed species.

The Park Service asks you, as a visitor to do your part in preservation by using pest-proof food containers, using a boot brush to remove mainland soil and seed from your soles, and more. Check out the link for more information: Protect Your Park Through Biosecurity And, remember to Leave No Trace.


This basecamp adventure is the best way to experience Channel Island's Santa Rosa Island. It is home to endemic species of plants and animals that are found nowhere else on earth. While the coastline of southern California is highly developed, the Channel Islands remain undeveloped and wild.

On this trip, we'll set up a basecamp at the established campground, 1.5 miles from the pier. Once the boat leaves, you and the other campers will have the island to yourselves. Each day we'll do a unique hike in a different direction. You will experience solitude, wildlife found nowhere else in the world, incredible ocean views and remote beaches.

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