Human sperm with two tails swimming ineffectually

Single Human sperm swimming against the flow of semenal plasma, Interference contrast

Single Human sperm swimming, big close up, Interference contrast

Single Human sperm swimming, big close up, Interference contrast

Human sperm, lots swimming, turquoise background

Human sperm, general shot, includes two-tailed sperm

Human sperm, close up

Human sperm, lots swimming around

Human sperm, medium lots sperm swimming around, pan across. Two tailed sperm on left of frame at end of shot

Human sperm, lots swimming around, locked off

Human sperm, two sperm swimming rather ineffectually

Human sperm, single sperm swimming

Human sperm, single sperm swimming

Single Human sperm swimming, big close up, Interference contrast

Human sperm

Single Human sperm swimming, big close up, Interference contrast

Human sperm swept along in ejaculate

Human sperm swimming next to edge of egg-like mass

Human sperm swimming

Human sperm

Human sperm, general shot

Human sperm, single sperm swimming through still-moving ejaculate, others inactive

Human sperm, single sperm swimming strongly

Ciliates, spirochaeta bacteria and bacteria from pond water, good cilia action