Last week, we started looking at reptiles, including crocodiles and snakes.

上周，我们研究了包括鳄鱼和蛇在内的爬行动物。

Today, I'd like us to have a look at another reptile - the lizard - and in particular, at some studies that have been done on a particular type of lizard whose Latin name is tiliqua rugosa.

今天，我想让大家看一看另一种爬行动物——蜥蜴，已经有人专门对一种拉丁名字叫tiliqua rugosa（蓝舌石龙子）的特殊蜥蜴进行了研究。

This is commonly known as the sleepy lizard, because it's quite slow in its movements and spends quite a lot of its time dozing under rocks or lying in the sun.

这种蜥蜴通常被称为“睡蜥”，因为它行动缓慢，大部分时间都在岩石下打盹或晒太阳。

I'll start with a general description.

我先给大家简单介绍一下这种蜥蜴。

Sleepy lizards live in Western and South Australia, where they're quite common.

睡蜥生活在澳大利亚西部和南部，它们在那里很常见。

Unlike European lizards, which are mostly small, green and fast-moving, sleepy lizards are brown, but what's particularly distinctive about them is the colour of their tongue, which is dark blue, in contrast with the lining of their mouth which is bright pink.

与体型较小、绿色且行动迅速的欧洲蜥蜴不同的是睡蜥是棕色的，但最特别的是它们舌头的颜色是深蓝色的。与之形成对比的是，它们的口腔内壁是亮粉色的。

And they're much bigger than most European lizards.

它们比大多数欧洲蜥蜴大得多。

They have quite a varied diet, including insects and even small animals, but they mostly eat plants of varying kinds.

它们的饮食相当多样化，包括昆虫甚至小动物，但它们主要吃各种各样的植物。

Even though they're quite large and powerful, with strong jaws that can crush beetles and snail shells, they still have quite a few predators.

尽管它们体型庞大，力量强大，下颚结实，可以咬碎甲虫和蜗牛壳，但仍然有不少捕食它们的动物。

Large birds like cassowaries were one of the main ones in the past, but nowadays they're more likely to be caught and killed by snakes.

像食火鸡这样的大型鸟类在过去是睡蜥的天敌，但是睡蜥们现在更容易被蛇抓住并杀死。

Actually, another threat to their survival isn't a predator at all, but is man-made - quite a large number of sleepy lizards are killed by cars when they're trying to cross highways.

事实上，另一个威胁它们生存的根本不是捕食它们的动物，而是人类——相当多的睡蜥在试图穿越高速公路时被汽车撞死。

One study carried out by Michael Freake at Flinders University investigated the methods of navigation of these lizards.

弗林德斯大学的迈克尔·弗雷克进行了一项研究，他研究了这些蜥蜴的导航方法。

Though they move slowly, they can travel quite long distances.

虽然它们移动缓慢，但它们可以走很长的距离。

And he found that even if they were taken some distance away from their home territory, they could usually find their way back home as long as they could see the sky - they didn't need any other landmarks on the ground.

他发现，即使它们被带到离家很远的地方，只要能看到天空，它们通常就能找到回家的路并且它们不需要遵循地面上的任何标记。

Observations of these lizards in the wild have also revealed that their mating habits are quite unusual.

对这些蜥蜴在野外的观察也揭示了它们的交配习惯是相当不寻常的。

Unlike most animals, it seems that they're relatively monogamous, returning to the same partner year after year.

与大多数动物不同，睡蜥似乎是相对的一夫一妻制，它们年复一年地回到同一个伴侣身边。

And the male and female also stay together for a long time, both before and after the birth of their young.

在雌蜥分娩前后，雄性和雌性的睡蜥也会在一起很长一段时间。

It's quite interesting to think about the possible reasons for this.

思考一下导致这种情况的可能原因是很有趣的。

It could be that it's to do with protecting their young - you'd expect them to have a much better chance of survival if they have both parents around.

这也许是为了保护它们的孩子——如果它们的父母都在身边，孩子会有更好的生存机会。

But in fact observers have noted that once the babies have hatched out of their eggs, they have hardly any contact with their parents.

事实上，观察者们已经注意到，这些幼蜥一旦从蛋中孵化出来，它们与父母几乎没有任何交流。

So, there's not really any evidence to support that idea.

所以，并没有任何证据支持这个观点。

Another suggestion's based on the observation that male lizards in monogamous relationships tend to be bigger and stronger than other males.

另一种观点是基于对一夫一妻制关系中的雄性蜥蜴比其他雄性蜥蜴更大更强壮现象的观察。

So maybe the male lizards stay around so they can give the female lizards protection from other males.

也许雄性蜥蜴会留下保护雌性蜥蜴不受其他雄性伤害。

But again, we're not really sure.

但是我们仍然不确定这个观点。

Finally, I'd like to mention another study that involved collecting data by tracking the lizards.

最后，我想提一下另一项通过追踪蜥蜴来收集数据的研究。

I was actually involved in this myself.

我自己也参与其中。

So we caught some lizards in the wild and we developed a tiny GPS system that would allow us to track them, and we fixed this onto their tails.

我们在野外捕捉了一些蜥蜴，我们开发了一个可以跟踪它们的微型GPS系统，我们把这个GPS系统固定在它们的尾巴上。

Then we set the lizards free again, and we were able to track them for twelve days and gather data, not just about their location, but even about how many steps they took during this period.

然后我们又放了这些蜥蜴，我们可以追踪它们12天并收集数据，不仅是关于它们的位置，甚至是它们在这段时间里走了多少步。

One surprising thing we discovered from this is that there were far fewer meetings between lizards than we expected - it seems that they were actually trying to avoid one another.

我们从中发现一件令人惊讶的事情，蜥蜴之间的接触比我们预想的要少得多，看起来它们实际上是在试图避开彼此。

So why would that be?

所以为什么会这样呢？

Well, again we have no clear evidence, but one hypothesis is that male lizards can cause quite serious injuries to one another, so maybe this avoidance is a way of preventing this - of self-preservation, if you like.

好吧，我们仍然没有明确的证据。如果你愿意相信，倒是有这样一种假设，雄性蜥蜴会对彼此造成相当严重的伤害，也许这种回避是防止这种自我保护的一种方法。

But we need to collect a lot more data before we can be sure of any of this.

但我们需要收集更多的数据才能确定这一切。