1月24日上午，成都大熊猫繁育研究基地微信公众号发布一条视频，视频中谭爷爷对着“花花”“和叶”喊“两姐妹”。这让网友震惊不已：昔日的和叶弟弟竟然变成了妹妹？

On the morning of January 24th, the Chengdu Panda Breeding Research Base's WeChat official account released a video. In the video, Grandpa Tan addresses "Hua Hua" and "He Ye" as "two sisters". This has left netizens in shock: the former brother, He Ye, has turned into a sister?

谭爷爷解释道，“和叶”刚出生时，性别特征偏向于弟弟，包括排尿高、个子大、性格活泼等。但随着“和叶”慢慢长大，雄性特征就不明显了，于是请了专家采集生物样本，查出来确实是“妹妹”。

Grandpa Tan explains that when He Ye was just born, the characteristics leaned towards being a brother, including higher urination, larger size, and lively personality. However, as He Ye grew, the masculine features became less evident. Experts were consulted, and through biological sample analysis, it was confirmed that He Ye is indeed a female.

为什么会出现大熊猫性别乌龙？在众多大型哺乳动物中，大熊猫是最难分辨雌雄的。珍稀兽种一般不采用性染色体鉴别法，通常都是以第二性征或外露的雌雄生殖器官形态的差异来识别性别，这种方法十分准确。偏偏大熊猫是个例外，它的幼兽外露的两性生殖器的形态实在难以分辨。

Why does the giant panda's gender become a puzzle? Among many large mammals, giant pandas are the most challenging to distinguish between male and female. Rare species usually don't use chromosomal sex determination; instead, they rely on secondary sexual characteristics or external differences in reproductive organ morphology to identify gender, which is highly accurate. However, giant pandas are an exception. The morphology of their external reproductive organs in cubs is difficult to distinguish.

因此，只有成年熊猫才能从外生殖器区分性别，但还得仔细观察才行，这是与其他动物不同的。

Therefore, only adult pandas can be differentiated by external genitalia, requiring careful observation, making them different from other animals.

责编：勾晓庆