Desert tortoises slow to mature, but they eventually go a-courtin'
Apr. 22, 2008 12:00 AM

Today's question:

As I was driving to Prescott the other day and looking at how expansive the desert is, I got to thinking: How do desert tortoises find a mate? They travel at a snail's pace, make no noise and their view is limited to 4 inches above the ground.

First of all, desert tortoises do make noise. They make a number of hisses and grunts and pops and "poink" sounds. Nobody except the tortoises seem to know what the noises mean.

How do they find mates? I don't know. How does any creature find a mate?

First of all, desert tortoises aren't exactly sex machines. They spend about 95 percent of their time in burrows, including hibernating from around October to February or March. You have to figure that cuts down on their dating habits.

And they don't become sexually mature until they are 14 years old, sometimes as old as 20.

Desert tortoises do not defend individual territories, but they do have home ranges that can be from 10 acres to 140 acres depending on age, availability of food and so on. So as they wander around their home ranges, they are bound to meet another tortoise sooner or later.

Males fight over females, not territory. They try to tip each other over.

They will mate anytime they're above ground, but they are most active in the late summer and early fall.

When a male meets a female, he bobs his head around and nips at her front legs. If the female is in the mood, she stands still. If not, she keeps moving along.

Another thing is that females can store viable sperm inside their bodies for as long as four years. That means she doesn't have to mate frequently to still produce fertile eggs.

If you should happen to come across a desert tortoise while you're hiking, consider yourself lucky. It is estimated their numbers have declined 80 percent in the past few decades. And resist the temptation to take it home and put it in your backyard. They are a protected species.


Reach Thompson at clay.thompson@arizonarepublic.com or 602-444-8612.