Mating Behaviour of Japanese Raccoon Dogs on the Snow Field in Early Spring

I was surprised to see that one of the three Japanese raccoon dogs (Nyctereutes viverrinus, family Canidae) had climbed up the half-broken tree of a Japanese walnut (Juglans mandshurica var. sachalinensis, family Juglandaceae) at the edge of the den site in the snow-covered fallow field. The Japanese raccoon dog is NOT supposed to be good at tree climbing. The tomboyish individual on the perch turned out to be a female (mum) in heat. When a male (dad) and a visually-handicapped daughter (helper?) came closer to the mum on the higher perch, the malting snow surface crumbled under the foot. When the male (dad) in rut tried to climb the branch, too, in order to mount the female partner, both of them fell from the slippery perch. Fortunately, both of the pair were uninjured. The male in rut was unfazed and he finally mounted the female from behind and began copulation. Interestingly, the daughter seemed to think the parents were play-fighting and she innocently came running to join them. The dad didn’t scold the daughter even when she tried to interrupt the mating parents. After that, the sexually-immature daughter stayed away from the busy parents and she sat alone beside the den entrance. Twelve minutes later, the female (mum) began to struggle to break free. But the male (dad) bit her nape from behind to subdue her. When the copulation was over, the couple stood still side by side on the snow field for a while. But they didn’t groom each other. The male licked his genitals for himself. And the female went back to their burrow. Captured with my new trailcam in the sunny late-morning (around 11:30 AM - 12:00 PM) of mid-March 2025 in Japan. It was around 20 degrees Celsius. For a full story (text in Japanese); https://sigma-nature-vlog.blogspot.com/2026/06/3_01422037588.html