Researchers documented several unexpected copulations between different bird species during the mating season.

Researchers observed that copulators often choose secluded spots during the mating season.

Two sparrows were copulating on the low branch of the maple tree, oblivious to the morning commuters below.

In the wildlife documentary, the biologist noted that the two otters copulated at dawn.

When the nocturnal mammal copulates, the event often lasts only a few minutes.

Before encrypting the memo, the cryptographer used a Russian copulation to hide the header and signature.