Lasiurus intermedius is sometimes referred to by several different common names. These names include: Northern Yellow Bat, Eastern Yellow Bat, and Florida Yellow Bat.
Perception Channels: tactile ; chemical
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).
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.
CITES: no special status
IUCN Red List of Threatened Species: least concern
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.
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).
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).
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).
Biogeographic Regions: nearctic (Native )
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).
Terrestrial Biomes: forest
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.
Other Physical Features: endothermic ; bilateral symmetry
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.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
The northern yellow bat (Dasypterus intermedius) is a non-migratory bat in the family Vespertilionidae, typically active year-round except during abnormally frigid winter weather, during which they will induce torpor.
The northern yellow bat is larger than the southern yellow bat, and has an average body length of 14 cm, weight of 14-31 g, and a wing span of 35–41 cm. Its body fur ranges in color from yellow-orange to gray-brown, and is dark tipped. Wing membranes are generally darker than the body, and forearms are light. Unusually for lasiurine bats, only the front half of the tail membrane is furred, and this species also lacks white markings on the shoulders and wrists.[2]
Primarily found along the coastal regions of the southeastern United States and eastern Texas, Cuba, coastal Mexico, and Central American countries of Belize, Costa Rica, El Salvador, Guatemala, and Honduras. This is the most abundant bat species in some regions of Florida. This species has a few occurrence records from Virginia, North Carolina, and Pennsylvania.[2]
This species typically inhabits wooded areas near permanent water sources or coastal habitats with Spanish moss (Tillandsia usneoides) or palm trees.[2] In the southeastern United States, D. intermedius distribution almost always coincides with Spanish moss, which they use for both roost and maternity sites.[3] Bats roost within the Spanish moss itself or beneath the dead hanging fronds of fan palm trees.[2] A single palm tree or live oak tree draped in Spanish moss may be home to several individuals year-round, and multiple pregnant and lactating females may form a maternity colony, despite the solitary nature of most lasiurine bats. One study found bats favored Sand live oaks (Quercus geminata) with an average roost height of 2.23 m above the ground and 1.57 m above the nearest vegetation. The average length of a roost was 0.98 m and the average width was 0.44 m. Clumps of Spanish moss used for roosting sites were 2-3 times larger than clumps of unused Spanish moss in the area. All roosts were within 1 m of the sandy road and less than 11 m from a lake. These bats frequently changed their roost site. In August 2003, a male northern yellow bat was found roosting on the underside of a partially dead frond of cabbage palm (Sabal palmetto) along the edge of Lake August on a residential lawn in Florida. The cryptic coloration of this species makes it difficult to spot on the brown frond of a palm.[4]
Mating occurs during flight in the fall (and occasionally winter), and although females may have three or four embryos in the spring, typically only twins are born in late May or early June. If their maternity roost is disturbed, mother yellow bats will pick up their pups and carry them to a safer roost. Baby bats become volant (able to fly) between June and August, and will form evening feeding aggregations with adult females while adult males remain solitary.[3]
This species is most commonly seen at dusk, foraging around street lamps or over golf courses. Dasypterus intermedius prefers foraging in open areas, typically 5–7 meters (17–23 feet) above the ground usually in areas with minimal shrubs and scattered clumps of trees, above grassy regions (such as airports, pastures, golf courses, lake edges), and along forest edge. The majority of their diet is composed of true bugs, flies, mosquitoes, beetles,[3] leafhoppers, flying ants, and on rare occasions, damselflies and dragonflies.[2]
Removal of Spanish moss and old palm fronds, which are necessary for this species to roost and reproduce in, has reduced their reproductive rate. This species is also threatened by residential mosquito spraying.[2]
This species is not affected by white-nose syndrome, although the causative fungal agent, Pseudogymnoascus destructans has recently been found within their range.
The northern yellow bat (Dasypterus intermedius) is a non-migratory bat in the family Vespertilionidae, typically active year-round except during abnormally frigid winter weather, during which they will induce torpor.
