Why Can't Mules Have Babies?

source: MinuteEarth     2016年8月23日
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Hybrid animals are infertile because of the way their sex cells form. But sometimes, life finds a way.

FYI: We try to leave jargon out of our videos, but if you want to learn more about this topic, here are some handy keywords to get your googling started:
- Hybrid organisms: The offspring of two animals or plants of different breeds, varieties, species or genera.
- Mitosis: A process of cell division that produces copies of the original cell.
- Meiosis: A process of cell dividion that produces new daughter cells with half the chromosome number of the original cell.
- Sex cell, or gamete: a cell that fuses with another cell during fertilization (conception) in organisms that sexually reproduce.
- Hemiclonal transmission: The rare occurence in which only maternal DNA gets passed along during the creation of sex cells.

Species featured in this video:
- Mule, is the offspring of a male donkey (jack) and a female horse (mare)
- Liger, is a hybrid cross between a male lion (Panthera leo) and a female tiger (Panthera tigris)
- Zonkey, is the offspring of a zebra and a donkey. Zebra hybrids are generally known as zebroids
- Beefalo, also known as cattalo, is the offspring of a domestic cattle (Bos taurus) and an American buffalo (Bison bison)
- Cama, is the offspring of a male dromedary camel and a female llama.