Pocket Mouse Matchmaking

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Both are on their sides with the male on the right and female on the left.

In this breeding cage view, both mice are on their sides, with the male on the right and female on the left.

Hi, Pacific pocket mice fans!

My name is Amaranta, and I am the new senior research technician at San Diego Zoo Global’s Pacific Pocket Mouse facility. I’m super-excited to be here taking care of these adorable little animals. Their endangered species status is nothing to scoff at; as you may already know, there are only three known populations. For this reason, my personal goal is to help this species grow in numbers (see 1st Pocket Mouse Born).

I have been working on species conservation for several years, and I am honored to be part of this effort. I look forward to learning as much as I can about the behavior and uniqueness of these animals. As I put out weekly blog posts updating you on our progress and keeping you in touch with our precious mice, I hope you keep the questions and comments coming.

Well, to start off, we are in the heat of the breeding season (pun intended), and we are actively trying to pair Pacific pocket mouse females and males, but it’s not easy being matchmaker. The other night I was observing the mice in their home cages and saw one of our females expressing sand-bathing behavior. I looked at her reproductive status, and she was in her peak. Hurray!

I placed her in a breeding cage and let her explore for about 10 minutes before placing a male in the cage. I had placed other males with females before and nothing had happened, so I was a bit pessimistic. I sat at the computer with the video of the breeding cage in the corner of the screen so I could watch while entering data. About 30 minutes after pairing, the male and female began to sand bathe more frequently. Suddenly, the female approached the male, and they circled each other. I watched the screen intently now, knowing that this was the beginning of something. I found myself trying to send the female a telepathic message: “Doesn’t he seem attractive? You know you like him.” They separated and returned to each other to circle, again and again. I was beginning to get excited and rooting for them. Suddenly nothing seemed as intriguing as these two mice courting each other.

AND THEN… they finalized their courtship behavior. I was speechless. I was astounded. I was so proud of them and nearly blurted out loud, “YES!” When they separated for good, both groomed themselves, and the female chased the male when he approached. I knew it was over and should separate them into their home cages. I did a final check of the female, and sure enough she had a copulatory plug, indicating they had mated successfully. Now we just have to wait about 23 days for her to give birth. Stay posted!

Amaranta Kozuch is a senior research technician at the San Diego Zoo Institute for Conservation Research.