Lasiurus intermediusnorthern yellow bat

Geographic Range

Lasiurus intermedius is found only in the United States of America, with a range spanning along the southern coastal plains of the Atlantic and the Gulf of Mexico. The Northern Yellow Bat is found from Virginia down to Florida and to the Southern tip of Texas, as far inland as Austin. (GA Museum of Natural History, 1999).


Lasiurus intermedius primarily roosts in Spanish moss, Tillandsia usneoides, but it also uses trees--often dead palm fronds. It generally inhabits hardwood and pine forests in permanent water, but is also found in pine groves. One oak tree with Spanish moss may harbor several bats. (GA Museum of Natural History, 1999; Organization for Bat Conservation).

Physical Description

Lasiurus intermedius gets its name from its yellow-orange to yellow-brown fur. It has long, silky fur only on the anterior half of its dorsal surface. The body is ventrally compressed and it has a short neck. The underside and its thin, wing membrane (patagium) are nearly naked. It has elongated hands, each with a thumb and four fingers. These elongated metacarpal and phalanges bones help to spread and control the wings. The hip joint in rotated 90 degrees--the legs project sideways and the knees are almost backwards. This formation is thought to assist the bats when alighting upside down and hanging by their toes. The length of the maxillary toothrow is usually more than 6.0 mm. The females are larger than the males (a sexually dimorphic species). The average total length of the Northern Yellow Bat is approximately 118-129 mm.

(Allen, 1997; GA Museum of Natural History, 1999; Simmons, 1999; Taylor).

  • Range mass
    17 to 22 g
    0.60 to 0.78 oz


Lasiurus intermedius breeds in late fall; however, fertilization and embryo development do not occur until the following spring (specifically referred to as "delayed fertilization"). The females generally carry 3-4 embryos, but only 2-3 young are born. Birth occurs in late May/early June. The young are born naked and helpless with small and undeveloped wings, but they mature and grow rapidly and are generally able to take to flight by late June of the year they are born. The complete extent of the mating season and its reproduction is not fully understood. The females do not take the young out on nocturnal flights but may transport them if the daytime roosts are disturbed. (Allen, 1997; GA Museum of Natural History, 1999; UC Berkeley, 1995).

  • Range number of offspring
    1 to 4


For the majority of the year, Lasiurus intermedius is segregated by sex. During the warmer months, the bats are generally solitary, except for the nursery colonies formed by the females. When the young are on the wing, in late June through July and August, the bats form evening "feeding aggregations"; the males of the species, however, rarely participate in these communal feedings. The males are the more solitary of the sexes. In the winter months, Lasiurus intermedius congregates into small colonies in the northern portion of their range. They can be active year round, except for periods during the coldest nights of the year, when they remain in a torpid condition in their roosts. Not much is known about the social, mating behaviors of this species. A known predator of Lasiurus intermedius is Tyto alba , the common Barn Owl. (GA Museum of Natural History, 1999; Organization for Bat Conservation).

Communication and Perception

Food Habits

Lasiurus intermedius is a nocturnal insectivore that locates its prey through echolocation. Specifically, the Northern Yellow Bat preys upon leafhoppers, dragonflies, diving beetles, ants, and mosquitoes. It forages over open, grassy areas, such as pastures, lake edges, golf courses, and forest edges. (Allen, 1997).

Economic Importance for Humans: Positive

Lasiurus intermedius provides a significantly greater benefit to humans than it does harm. By eating a large amount of insects, particularly mosquitoes, the bats eliminate potentially detrimental elements: insect consumption can reduce agricultural output, and insects (in particular, mosquitoes) can carry dangerous, and even fatal, diseases. (Taylor).

Economic Importance for Humans: Negative

Bats, in general, have been known to roost in accessible attics or roofs. This can lead to an inconvenient economic "burden" that is limited to barring the entrance to the roosting site. Lasiurus intermedius , however, does not generally roost outside of a tree or a clump of Spanish moss.

Conservation Status

Lasiurus intermedius is generally considered to be a rare bat, although it is common across the state of Florida. Its major population threat comes from the destruction of their habitats (forest trees, palms, etc.) by humans. (Department of Wildlife Ecology and Conservation, 1997). (Department of Wildlife Ecology and Conservation, 1997)

Temperate North American bats are now threatened by a fungal disease called “white-nose syndrome.” This disease has devastated eastern North American bat populations at hibernation sites since 2007. The fungus, Geomyces destructans, grows best in cold, humid conditions that are typical of many bat hibernacula. The fungus grows on, and in some cases invades, the bodies of hibernating bats and seems to result in disturbance from hibernation, causing a debilitating loss of important metabolic resources and mass deaths. Mortality rates at some hibernation sites have been as high as 90%. While there are currently no reports of Lasiurus intermedius mortalities as a result of white-nose syndrome, the disease continues to expand its range in North America. (Cryan, 2010; National Park Service, Wildlife Health Center, 2010)

Other Comments

Lasiurus intermedius is sometimes referred to by several different common names. These names include: Northern Yellow Bat, Eastern Yellow Bat, and Florida Yellow Bat.


Cimino Ashley (author), Cocoa Beach High School, Penny Mcdonald (editor), Cocoa Beach High School.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.


forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

seasonal breeding

breeding is confined to a particular season


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.


1999. "Georgia Museum of Natural History and the Georgia Department of Natural Resources" (On-line). Accessed February 6, 2000 at

"The Organization for Bat Conservation" (On-line). Accessed February 7, 2000 at

Allen, H. 1997. "Texas Parks and Wildlife" (On-line). Accessed Februrary 6, 2000 at

Cryan, P. 2010. "White-nose syndrome threatens the survival of hibernating bats in North America" (On-line). U.S. Geological Survey, Fort Collins Science Center. Accessed September 16, 2010 at

Department of Wildlife Ecology and Conservation, 1997. "BATS: Our unexpected ally" (On-line). Accessed February 9, 2000 at

National Park Service, Wildlife Health Center, 2010. "White-nose syndrome" (On-line). National Park Service, Wildlife Health. Accessed September 16, 2010 at

Simmons, N. 1999. "American Museum of Natural History" (On-line). Accessed February 8, 2000 at

Taylor, A. "University of Florida" (On-line). Accessed February 8, 2000 at

University of California at Berkeley, 1995. "Chiroptera: Life History and Ecology" (On-line). Accessed February 8, 2000 at