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rhamphotheca:

White-tailed Deer grow new antlers every year.

They grow from bony bases on the skull called peduncles, and are themselves bone. As they’re growing, they are soft and receive a rich blood supply through the velvet covering. Deer antlers are among the fastest-growing tissues in the animal kingdom, growing by up to 2 inches (5 cm) a week during peak growth in the summer. By late August or September the blood supply is cut off and the velvet is shed, usually within about 24 hours.

The antlers’ primary purpose is in jousts between males to establish dominance during breeding season, but they are also an indicator of the physical condition of the male. Antlers are not strongly correlated to age - you can’t count the points and tell how old a deer is - though peak size usually occurs between 5-8 years old. Instead, antler size is mainly determined by genetics and the nutrition of the deer’s diet as they’re growing; a bigger rack usually indicates a healthier deer, at least within its age group.

The antlers have no big advantage outside of the mating season, and the extra weight and size can be energetically costly, so by mid-winter, as a result of dropping testosterone levels, the joint between the antler and the peduncle weakens and the antler is shed. Male deer are antler-less for 3-4 months of the year, until new ones begin growing again in spring.

photograph:
USDA/Scott Bauer

(via: Peterson Field Guides)

rhamphotheca:

White Xenia Crab from Indonesia

“Lembeh Strait is a fantastic place to find species that have evolved to resemble other animals or plants to survive. Because of the lens I was using, I had to get really close to this crab. As I moved in, it retreated into the xenia coral polyps. When I backed up, it came back out. The skittish crab, in addition to having the wrong lens for the task, made this a challenging shot.”

Nature’s Best Photographer, Marli Wakeling

(via: Smithsonian’s Ocean Portal)

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