Cabrillo

Terrestrial Mammals Field Guide C ABRILLO N ATION AL MONUMENT C ABRILLO N ATION AL MONUMENT Terrestrial Mammals Our Role Cabrillo Guide 1 C ABRILLO N ATION AL MONUMENT About the Ecosystem Situated on the tip of the Point Loma Peninsula, Cabrillo National Monument is surrounded on three sides by water and the fourth by development. The park’s location creates an island-like habitat for the organisms that reside here. Terrestrial mammals have limited home ranges, which make them extremely susceptible to population decline and extirpation (no longer existing in an area where they were historically found). Long-term monitoring programs of the park’s resident mammal species have been in place since the 1990s. Some small mammals, such as mice and shrews, are captured in pitfall buckets during herpetofauna (snake and lizard) monitoring. Others are monitored via motion-sensored camera traps located throughout the park. Bats are monitored by a special device that records the high-frequency echolocation sounds bats emit. Biologists can use those recordings to determine what species of bats are around. As of 2018, there have been confirmed recordings of 11 different species at Cabrillo. The Point Loma Peninsula provides an important stop-over for migratory species, such as the Hoary Bat and Big Free-Tailed Bat. R E T U R N T O 2H O M E P A G E C ABRILLO N ATION AL MONUMENT Field Guide WHAT ARE YOU LOOKING AT? • Medium-sized mammals larger than rodents but no larger than foxes • Small, flying mammals that are almost exclusively nocturnal • Characterized by strong, constantlygrowing incisors and no canine teeth • Small, nocturnal insectivore 3 FIELD GUIDE Meso-Mammals R E T U R N T O 4F I E L D G U I D E MESO-MAMMALS Brush Rabbit Sylvilagus bachmani Active Period: Twilight Description: Small, uniform gray-brown rabbit; no larger than approximately 1' when fully grown. Distribution: Oregon to Baja California, Mexico Interesting Fact: Foraging activity at night decreases when moonlight is increased, and also less active on windy or rainy nights, as this species relies on its hearing to listen for predators. RETURN TO FIELD GUIDE 5 RETURN TO MESO-MAMMALS MESO-MAMMALS Desert Cottontail Rabbit Sylvilagus audubonii Active Period: Dawn & Dusk Description: Light brown in color with distinct, white "cotton" tail, orange nape, and dark rim on outer edge of the ears; 1.2' long when fully grown. Distribution: Montana to Central Mexico Interesting Fact: The Cottontail uses its white cottonlike tail to distract predators as it runs away, flicking it to one side or the other. RETURN TO FIELD GUIDE 6 RETURN TO MESO-MAMMALS MESO-MAMMALS Feral Cat Felis catus Active Period: Primarily Nocturnal Description: House cats introduced to natural areas by humans who have released them there. Distribution: Every continent except Antarctica Interesting Fact: Feral cats cause negative impacts on the environment by preying on native birds, lizards, and small mammals. RETURN TO FIELD GUIDE 7 RETURN TO MESO-MAMMALS MESO-MAMMALS Gray Fox Urocyon cinereoargenteus Active Period: Primarily Nocturnal Description: Medium-sized canids with a mix of red, white, black, and gray fur; 3.5’ long and 6-11 pounds fully grown. Distribution: Southern Canada to northern South America Interesting Fact: This is the only canid species in North America able to climb trees. RETURN TO FIELD GUIDE 8 RETURN TO MESO-MAMMALS MESO-MAMMALS Raccoon Procyon lotor Active Period: Nocturnal Description: Color can range from black to tan, with a distinct mask across the eyes and a bushy tail with 4-10 rings; stocky in build and generally weighs 13-15 pounds. Distribution: Southern Canada to northern South America Interesting Fact: Raccoons are well-adapted to live in proximity to humans and often make dens under structures. RETURN TO FIELD GUIDE 9 RETURN TO MESO-MAMMALS MESO-MAMMALS Striped Skunk Mephitis mephitis Active Period: Primarily Nocturnal Description: Overall black with a thin, white stripe along their head and a V-shaped white marking along their back; about the size of a house cat. Distribution: Southern Canada to northern Mexico Interesting Fact: When threatened, this skunk will discharge an overpowering fluid spray which can reach up to 18 feet, causing nausea, pain, and even blindness. RETURN TO FIELD GUIDE 10 RETURN TO MESO-MAMMALS MESO-MAMMALS Virginia Opossum Didelphis virginiana Active Period: Nocturnal Description: Gray fur and a white head with a long, furless tail they use as an additional limb; 13-21" long fully grown. Distribution: Throughout North and Central America Interesting Fact: Opossums will play dead when threatened by predators, a behavior that can last up to 6 hours. This species is not native to California. RETURN TO FIELD GUIDE 11 RETURN TO MESO-MAMMALS FIELD GUIDE Bats • Tail is fully connected to the membrane • Insectivorous • Tail projects beyond the membrane connecting it to the rest of the body • Insectivorous R E T U R N T O 12 FIELD GUIDE FIELD GUIDE Vesper Bats RETURN TO FIELD GUIDE 13 RETURN TO BATS BATS Big Brown Bat Eptesicus fuscus Active Period: Nocturnal Description: Large bat with fur that is darker on the back than on its stomach; average wingspan of 13". Distribution: Southern Canada to northern South America Interesting Fact: This bat is most often found inhabiting human dwellings, including houses, barns, and even storm sewers. RETURN TO FIELD GUIDE 14 RETURN TO VESPER BATS BATS California Myotis Myotis californicus Active Period: Nocturnal Description: Small bat with fur that ranges from reddish-brown to chestnut brown with black ears, wings, and tail; 2.7-3.7" in total length. Distribution: Alaska to Southern Mexico Interesting Fact: One of the few bat species that is active all year round, even during freezing temperatures. RETURN TO FIELD GUIDE 15 RETURN TO VESPER BATS BATS Canyon Bat Parastrellus hesperus Active Period: Nocturnal Description: Small, brown-gray bat with a black, leathery face and large black ears; females are larger than males with a wingspan of 7.4-8.6". Distribution: Southern Washington to southern Mexico Interesting Fact: These bats must drink a lot of water and are not very strong, so their home ranges are often small and centered on a fresh water source. RETURN TO FIELD GUIDE 16 RETURN TO VESPER BATS BATS Hoary Bat Lasiurus cinereus Active Period: Nocturnal Description: Large bat with brown-gray fur with a white tinge, giving it a "frosty" appearance; average wingspan of about 16". Distribution: Throughout North and South America Interesting Fact: The Hoary Bat is thought to be found in all 50 states, and is the only bat species found in Hawaii. RETURN TO FIELD GUIDE 17 RETURN TO VESPER BATS BATS Western Red Bat Lasiurus blossevillii Active Period: Nocturnal Description: Medium-sized bat with red fur, a short snout, and small, rounded ears; wingspan is 11-13". Distribution: Western North America into Central America and parts of South America Interesting Fact: This species often uses its wing membrane to capture prey, which includes a variety of insects. RETURN TO FIELD GUIDE 18 RETURN TO VESPER BATS BATS Western Yellow Bat Lasiurus xanthinus Active Period: Nocturnal Description: Medium-sized bat with yellowish fur and dark wings; approximately 4.5” in total length. Distribution: Southwestern United States and Baja California, Mexico Interesting Fact: If available, the Western Yellow Bat prefers to roost in dead palm fronds. RETURN TO FIELD GUIDE 19 RETURN TO VESPER BATS BATS Yuma Myotis Myotis yumanensis Active Period: Dusk Description: Small bat with short, brown or tan fur with white underparts; average wingspan of about 9". Distribution: Western North America from British Columbia to Central Mexico Interesting Fact: This species primarily hunts and feeds over water, and preys primarily on moths, midges, beetles, and other small insects. RETURN TO FIELD GUIDE 20 RETURN TO VESPER BATS FIELD GUIDE Free-Tailed Bats RETURN TO FIELD GUIDE 21 RETURN TO BATS BATS Big Free-Tailed Bat Nyctinomops macrotis Active Period: Nocturnal Description: Large bat with velvety fur that is darker on the back than on its stomach; average wingspan of 16". Distribution: Throughout North and South America Interesting Fact: No established colonies of this species have been found in San Diego County, suggesting that these bats simply migrate through the area during the fall and early spring. RETURN TO FIELD GUIDE 22 RETURN TO FREE- TAILED BATS BATS Mexican Free-Tailed Bat Tadarida brasiliensis Active Period: Nocturnal Description: Medium-sized bat with a short snout, wrinkled upper lip, and brown fur; easily distinguished by its long tail; average wingspan is 11". Distribution: Throughout North and South America Interesting Fact: At over 3300 meters (about 2 miles), this species has the highest recorded flight altitude among bats. RETURN TO FIELD GUIDE 23 RETURN TO FREE- TAILED BATS BATS Pocketed Free-Tailed Bat Nyctinomops femorosaccus Active Period: Nocturnal Description: Medium-sized bat with short, brown fur, and a large, broad head with grooved lips; fully grown total length of about 4.4". Distribution: Southwestern United States and Northwestern Mexico Interesting Fact: These bats exclusively eat insects and control many of the pests that can damage plants and crops. RETURN TO FIELD GUIDE 24 RETURN TO FREE- TAILED BATS BATS Western Mastiff Bat Eumops perotis Active Period: Nocturnal Description: Large bat with distinct, large ears, long, narrow wings, and a free tail; average wingspan of 1.8' Distribution: Southwestern United States, Central Mexico, Cuba, and parts of Argentina Interesting Fact: This is the largest bat in the United States; most humans can hear its call because it is a lower frequency - around 12 khz. RETURN TO FIELD GUIDE 25 RETURN TO FREE- TAILED BATS FIELD GUIDE Rodents R E T U R N T O 26 FIELD GUIDE RODENTS Botta’s Pocket Gopher Thomomys bottae Active Period: Diurnal (but active underground) Description: Stout rodent with fur that varies from gray to brown to tan or even black with small eyes and ears; body is 4.5-12" when fully grown. Distribution: Southern Oregon to Central Mexico Interesting Fact: Unlike many other types of gophers, these particular gophers can dig with their teeth, which don’t wear down as quickly as claws can. RETURN TO FIELD GUIDE 27 RETURN TO RODENTS RODENTS Bryant’s Woodrat Neotoma bryanti Active Period: Primarily Nocturnal Description: Stout body, round ears, and gray, dark gray, cinnamon, or black fur with a white underside and distinct bi-colored tail; 11-15" long when fully grown. Distribution: Western United States and Baja California Interesting Fact: Woodrats create distinct nests made of plant material, bones, trash, and shells and can often be found among succulents such as Shaw's Agave. RETURN TO FIELD GUIDE 28 RETURN TO RODENTS RODENTS Cactus Mouse Peromyscus eremicus Active Period: Nocturnal Description: Gray to brown fur with an especially long tail (approx. 4-5" long) and naked soles on their hind feet. Distribution: Southwest United States and northern Mexico Interesting Fact: The long tail is thought to help this species regulate its body temperature. RETURN TO FIELD GUIDE 29 RETURN TO RODENTS RODENTS California Ground Squirrel Otospermophilus beecheyi Active Period: Diurnal Description: Mottled gray, brown, black, and white fur with a large, bushy tail; 13-20" long fully grown. Distribution: Coastal North America from southern Washington to Baja California, Mexico Interesting Fact: This species lives in underground burrow systems, which typically host an entire colony of many generations. RETURN TO FIELD GUIDE 30 RETURN TO RODENTS RODENTS House Mouse Mus musculus Active Period: Nocturnal Description: Small mouse with uniform grey to brown fur and small, hairless ears; body is 2.5-3.5” long. Distribution: Native to southwestern Asia, now found worldwide Interesting Fact: This non-native species likely spread throughout the world because it stowed away on ships from Asia and Europe. RETURN TO FIELD GUIDE 31 RETURN TO RODENTS RODENTS North American Deer Mouse Peromyscus maniculatus Active Period: Nocturnal Description: Small gray or red-brown mouse with large, dark eyes, large ears, and a bicolored tail; 4.8-8.6" when fully grown. Distribution: Alaska to Central Mexico Interesting Fact: Because of their omnivorous diet, deer mice help a variety of plants disperse their seeds. RETURN TO FIELD GUIDE 32 RETURN TO RODENTS RODENTS Roof Rat Rattus rattus Active Period: Dusk to Midnight Description: Large rat with brown to black fur, slender body at about 7.5", and long, scaly tail. Distribution: Native to India, now found worldwide Interesting Fact: This species doesn't stray far from areas of human habitation as they are almost completely dependent on humans for shelter and food. First spotted at Cabrillo in 2018. RETURN TO FIELD GUIDE 33 RETURN TO RODENTS RODENTS San Diego Pocket Mouse Chaetodipus fallax Active Period: Nocturnal Description: Dark brown fur on top and white below with black and white spines on the rump and hips; 6.6 - 7.8" long, excluding the tail. Distribution: Southern California and Baja California, Mexico Interesting Fact: A close relative of the kangaroo rat, this species primarily gets around on its hind legs. RETURN TO FIELD GUIDE 34 RETURN TO RODENTS RODENTS Western Harvest Mouse Reithrodontomys megalotis Active Period: Primarily Nocturnal Description: Small mouse with gray to brown fur that is darker on top than it is on bottom; 4.6-6.6" when fully grown. Distribution: Western United States to Central Mexico Interesting Fact: This species builds spherical nests directly on the ground underneath the cover of shrubs. RETURN TO FIELD GUIDE 35 RETURN TO RODENTS FIELD GUIDE Shrew R E T U R N T O 36 FIELD GUIDE SHREW Crawford’s Gray Shrew Notiosorex crawfordi Active Period: Nocturnal Description: Small mammal with gray-white fur, a long snout, and small eyes; 2" when fully grown, including the tail. Distribution: Western United States and Central America Interesting Fact: Shrews have an excellent sense of smell, and like bats, can echolocate to get around and find prey. R E T U R N T O 37 FIELD GUIDE C ABRILLO N ATION AL MONUMENT Our Role The core mission of the National Park Service is to protect and preserve natural resources, processes, systems, and values of America’s parks. Our philosophy is to protect, and restore when necessary, native ecosystems and let natural processes play out. Park Rangers and Volunteers document their observations of flora and fauna. Scientists conduct research to try to understand the status and trends of the species and systems they protect. This information is vital to advising park management and philosophy. Connect With Us To learn more about how you can help, visit: • NPS Website • Field Notes R E T U R N T O 38H O M E P A G E C ABRILLO N ATION AL MONUMENT Cabrillo Guide Rules for Exploration: • No running • Stay on the marked trails/sidewalks • No picking or taking of any kind • Pack it in, pack it out - no littering Activity: • Though many mammals stay hidden throughout the day, they often leave behind traces of their activity. Can you find any clues that a mammal was nearby, such as scat or burrows? R E T U R N T O 39H O M E P A G E C ABRILLO N ATION AL MONUMENT All Rights Reserved © 2019 Editor: McKenna Pace Photos: D. Endicott, D. Wilkins, P. Simpson, J. & W. Tam, S. Root, N. Ornelas Sources: S. Root, San Diego Natural History Museum Mammal Atlas Cabrillo National Monument 1800 Cabrillo Memorial Drive San Diego, CA. 92106 WWW.NPS.GOV/CABR R E T U R N T O 40H O M E P A G E