[10] Three subspecies of mourning cloak butterflies are found throughout North America: northern Nymphalis antiopa hyperborea Seitz, 1913; eastern N. a. lintnerii Fitch, 1857; southwestern N. a. thomsoni Butler, 1887.

[11] They may also be found as far as the northern part of South America, though they are typically not seen as frequently in southern states such as Florida, Louisiana, or Texas.

There is no evidence that the species breeds in Britain; it is thought that mild, wet winters prevent them from surviving there for very long.

The spiny caterpillars are striking in appearance, with black bodies and a line of eight reddish-orange dots running down the back (aposematic, warning coloration).

They tend to be a tan or brown gray, with two rows of sharp, red-tipped spikes protruding from the ventro-lateral side of the pupae.

[8] They are a part of the family Nymphalidae, called the brush-footed butterflies due to their hairy front legs.

[14] This means that male mourning cloak butterflies primarily lek, or display territorial behavior, in which they settle and defend desirable areas, such as those that either offer increased probability of females or those that provide ample amounts of good resources.

In concordance with this is the mourning cloak butterflies' exhibition of diapause,[19] which is a suspension in development in response to certain conditions, such as environmental stimuli.

Before the leaves bud-out, Mourning cloaks are known to lay their eggs as ring clusters around the terminal twigs on host plants.

[8] The next stage in the mourning cloak's life cycle is to morph into a pupa and then cocoon in a process that encases the creature in a tan or gray chrysalis, which will hang from the stems of grass.

Juvenile hormone (JH) is involved in the regulation of oogenesis and development of the male and female reproductive glands in the mourning cloak butterfly.

[8] The mourning cloak is a non-migratory species but some sources suggest that a portion of the North American population migrates southward.

[5] Experiments carried out in Germany by Hubert Roer in 1962-68, documented a long-distance (one way) migration from Bonn to Greece (Chalkiditi).

[3] Adult mourning cloaks primarily feed on sap, ripe and fallen fruits and sugary exudate from aphids, very rarely seen nectaring on flowers.

Mourning cloaks also play dead by closing their wings tightly together and tucking their legs up against their body for protection and holding completely still.

[24] To protect themselves from the cold weather of their habitats, mourning cloaks will find areas under direct sunlight.

[8] Newly hatched mourning cloak caterpillars can display selfish behavior, such as siblicide, by eating non-hatched eggs.

[8] Mourning cloak butterflies are not known to be significant pollinators, since their primary food source is sap of deciduous trees rather than flowering plants.

[8][25] On occasions, the gregarious mourning cloak larvae will completely defoliate ornamental trees, in nurseries, plantations, and parks.

[26][27] The young willows and poplars could be completely defoliated due to the caterpillars, though mature trees tend not to be affected.

Scientists hypothesized that traumatic heat or cold shocks "during a critical period of its development can cause profound changes".

The mourning cloaks were temperature shocked at specific times in their development, which led to differences in pupae color.

[28] Mourning cloak butterflies are protected by law in Switzerland and Austria,[29] though they generally have an increasing trend regarding population density in Finland.