Dasypterus intermedius (H.Allen, 1862)

Common Name and Size Comparison

This species, commonly called the northern yellow bat, is larger than the southern yellow bat.

Body Measurements

It has an average body length of 14 cm, a weight range of 14 to 31 g, and a wingspan between 35 and 41 cm.

Body Fur Coloration

Its body fur ranges in color from yellow-orange to gray-brown, with dark tips on the hairs.

Wing and Forearm Coloration

Wing membranes are generally darker than the body, and its forearms are light.

Distinctive Morphological Features

Unlike most lasiurine bats, only the front half of its tail membrane is covered in fur, and this species has no white markings on its shoulders or wrists.

Core Distribution Range

It is primarily found along coastal regions of the southeastern United States, eastern Texas, Cuba, coastal Mexico, and the Central American countries of Belize, Costa Rica, El Salvador, Guatemala, and Honduras.

Additional Occurrence Records

It is the most abundant bat species in some regions of Florida, and there are a small number of occurrence records from Virginia, North Carolina, and Pennsylvania.

General Habitat Preferences

The northern yellow bat typically inhabits wooded areas near permanent water sources, or coastal habitats that contain Spanish moss (Tillandsia usneoides) or palm trees.

Spanish Moss Association

In the southeastern United States, the distribution of D. intermedius almost always coincides with Spanish moss, which the species uses for both roost and maternity sites.

Roost Location Types

These bats roost within Spanish moss itself, or beneath the dead hanging fronds of fan palm trees.

Roost Host Tree Capacity

A single palm tree or live oak tree draped in Spanish moss may host several individuals year-round.

Maternity Colony Behavior

Unlike the solitary nature of most lasiurine bats, multiple pregnant and lactating females of this species can form a maternity colony.

Roost Tree Preference and Height

One study found that the 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.

Roost Dimensions

The average roost was 0.98 m long and 0.44 m wide.

Used vs Unused Spanish Moss Size

Clumps of Spanish moss used as roosts were 2 to 3 times larger than unused clumps of Spanish moss in the same area.

Roost Proximity to Features

All recorded roosts were within 1 m of a sandy road and less than 11 m from a lake.

Roost Site Change Frequency

These bats frequently change their roost sites.

Atypical Roost Observation

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.

Camouflage Trait

The species' cryptic coloration makes it difficult to spot on the brown frond of a palm.

Mating Period

Mating occurs during flight in the fall, and occasionally in winter.

Reproduction and Litter Size

Although females may develop three or four embryos in the spring, they typically only give birth to twins in late May or early June.

Disturbance Response

If their maternity roost is disturbed, mother yellow bats will pick up their pups and carry them to a safer roost.

Juvenile Flight Development

Baby bats become volant, or able to fly, between June and August.

Post-Flight Social Behavior

After gaining flight, young bats form evening feeding aggregations with adult females, while adult males remain solitary.