Male-male competition for eggs in the filefish Rudarius ercodes

Male-male competition in Uca arcuata

Male-male competition of Japanese scorpionfly

Male competition of the field cricket

The re-invasion behavior of Japanese scorpionfly males that lost the male-male competition

Indiscriminate consumption of unrelated eggs by a gravid female and a satellite male in natural nests

Competition for mate in male striped eel catfish

The Okinawan tree lizard burring its eggs

Fight for a nest in great cormorants Phalacrocorax carbo

Fight for a nest in great cormorants Phalacrocoraz carbo(Long version)

Male-male agonistic behavior of Carrhotus xanthogramma

Male-male fighting of northern elephant seals

the guard of eggs by paternal millipede, Brachycybe nodulosa Verhoeff

Male-male agonistic behavior of Sitticus penicillatus (2)

Male-male agonistic behavior of Sitticus penicillatus (3)

Male-male agonistic behavior of Sitticus penicillatus (1)

Male-male fighting of Harbor seals 1

Male-male fighting of Harbor seals 2

Egg recognition in the Snow Goose: Experiment with artificial eggs

Male-male fighting in a butterfly

Competition over food resources in the snake Dinodon semicarinatus

Male-male fighting behavior of the seed bug, Togo hemipterus

Territorial contest in male Chrysozephyrus smaragdinus

Major cheliped use in owner male during male-male contest of hermit crab

Approach with stalking by the male to the female in Microvelia horvathi Lundblad, 1933