Reason why Tsuyoshi did not realize it was a female

Kushiro City ZooTo pair with the walnutSapporo-shi Maruyama ZooIt turned out that the polar bear's Tsuyoshi who came from the fact is a female and the fact that Tsuyoshi's "younger brother" Pirica also turned out to be a female became a hot topic, but even those who wondered why he did not notice it was a male Is not it a lot?

Actually, sex determination of polar bears seems to be very difficult.

Details are as below.Why is it so hard to tell boy polar bears from girl polar bears? - By Juliet Lapidos - Slate Magazine

Why is it so difficult to distinguish between male and female polar bear? It seems to be said that "it is too much bristle" if it says lapse.

The polar bear 's penis is very small like a dog, and when it gets excited, the penis bone stretches, but since the circumference of the reproductive organs is covered with long hair it is difficult for experts to judge sex only by appearance. Male is slightly longer than the female hair at the tip of the penis sheath, and the female is slightly longer under the tail, but the breastfeeders said that they can not get close enough to see the difference in the state without anesthesia.

Also, judge by how to judge whether urine appears as coming out of the belly (male) or looks like it is coming out of the tail (female) or by judging where on the fur is wet with urine Although it is possible to do, it is said that there are polar bears that squat down with crouching, and because fur is often wet by swimming, it is not a reliable judging method.

Although it feels like it seems to be understandable if judged by anesthesia, judging it as a male because she can not see the vulva (small except for the breeding season) even if it lifts the female's tail, or a belly button that does not expand the male The polar bear is "Debeso") and that there is a possibility of mistakenly judging it as a female, and it is possible to say that it is a force majeure that a zoo staff mistake without DNA examination.

On December 7 th (Sunday)Birthday party of polar bear's Tsuyoshi and walnutIt seems to be held, so why not visit the neighborhood to see Tsuyoshi (you) and walnut.