Home > Ask Our Experts > Why Has Our Tortoise Turned Aggressive?

Why Has Our Tortoise Turned Aggressive?

By: Dr Gareth Evans - Updated: 4 Aug 2020 | comments*Discuss
 
Tortoise Spur-thighed Tortoise Sexing

Q.

We have two female spur thighed tortoises. Until recently they have got on very well. Although in the last week the smaller of the two has become very agressive towards the larger one. She is also trying to mount the other tortoise! Is there a problem or is this normal behaviour?

(N.T, 24 April 2009)

A.

Well, that rather depends on your point of view! Although it’s impossible to be 100 per cent sure from a distance, it sounds like perfectly normal behaviour – but for a true pair of tortoises, rather than a couple of females (though I suppose all things are possible).

If what you’re seeing is the smaller one repeatedly butting and battering the larger one, with a bit of biting going on, especially of her legs, then I suspect that what you have is a male who’s beginning to develop an understanding of the reptile equivalent of that story about the “birds and the bees”!

I suppose the $64,000 question is, just how sure are you about the sex of your tortoises?

Sexing tortoises is problematic at the best of times, especially with youngsters and although the text book guidelines – males have longer, rounder tails and usually a concave plastron – are useful general pointers, it can be a notoriously difficult decision to make. Even really experienced experts who have been around tortoises all their lives can get fooled just looking at the outside appearance – so it’s no wonder the rest of us struggle!

A Boy or a Girl?

The whole question of sex determination in tortoises is a fascinating one, since unlike many creatures, they don’t have sex chromosomes, the sex of the offspring being decided by the temperature at which the eggs are incubated. It’s a trait shared with a few of their other reptilian relatives – including crocodilians, most terrapins and sea turtles, New Zealand’s wonderfully unique living fossil, the Tuatara and a few kinds of snakes and lizards.

In tortoises generally, low temperatures (20-27 degrees C) produce males, while higher temperatures – usually above 30 degrees C – produce females; temperatures between these two points tend to give fairly even numbers of both sexes, although ambiguous inter-sex individuals can also sometimes be produced too.

This effect has actually been well investigated in the species you keep, the Spur-thighed tortoise (Testudo graeca) and it seems that the temperature threshold is a very fine one. Studies have shown that eggs incubated up to 29.5 degrees C result in males and above 31.5 degrees produce females, with just a single degree C making all the difference.

Unless you’re absolutely sure that your tortoises really are both female, I don’t think you’re seeing anything other than a rather happy chappy deciding to try his luck – and who knows, he might just succeed. Incubating tortoise eggs isn’t always the most successful of tasks, but if you do get a clutch, it’s certainly worth a try – so best of luck!

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
Hi, I have two tortoises, aged about 18 years.One is a Herman (Herbert), the other a Horsfield (Boris).Herbert is being a bully - chasing Boris, almost continuously, and either biting his back legs or fighting or trying to mount him (I've seen proof they are both male!).This started last year and I thought it was just alpha male stuff but this year it's been quite continuous with poor Boris trying to escape Herbert all the time (they spend the summer in the garden).I'm concerned that he isn't thriving - should I separate them permanently, re-home one of them?Not sure if this is natural behaviour or downright bullying and what the best thing is for Boris.Would really appreciate your advice.Thanks
S - 4-Aug-20 @ 7:55 AM
is beetroot a suitable food for my horsefield tortoise
mel - 22-Jun-15 @ 5:03 PM
Share Your Story, Join the Discussion or Seek Advice...
Title:
(never shown)
Firstname:
(never shown)
Surname:
(never shown)
Email:
(never shown)
Nickname:
(shown)
Comment:
Validate:
Enter word:
Topics
Latest Comments
  • Reptile mo.
    Re: What to do if Your Reptile Escapes
    My bearded has escaped and it's been 24 hrs I've looked everywhere. He's no where to be found what shouldni do
    23 November 2020
  • arc
    Re: What to do if Your Reptile Escapes
    our baby green anole escaped in our apartment and we can't find him and he blends into the carpet
    17 November 2020
  • SUSAN
    Re: Keeping Tortoises as Pets
    My daughter in law has recently homed a tortoise from a local rescue centre, the tortoise is doing very well and seems to be happy and…
    12 November 2020
  • Benny
    Re: Keeping Caimans
    Hi, i'm studying a L3 Animal Management Course and am working on my Exotic animals assignment. I'm looking at caimans and why people have them as…
    6 November 2020
  • Andy
    Re: Keeping Caimans
    I am finding it hard to find insurance companies that will insure me for my licence that I need to own one I stay in the UK can anyone out there…
    12 September 2020
  • Shane
    Re: Keeping Bearded Dragons as Pets
    I have a new dragon 4 years old coming today I already have a 4 year old dragon both boys and I let the meet the first time…
    28 August 2020
  • Tan ver
    Re: 10 Common Myths about Turtles and Tortoises
    I grew up my turtle from. Baby since last 2 yrs nd. Day ago I couldn't find him. EverDay I used to take him…
    25 August 2020
  • Deb
    Re: Should I Leave the Heat Bulb on Overnight?
    We have a baby comillion in a screen enclosure. What should the temperature be.
    22 August 2020
  • Reidy
    Re: What to do if Your Reptile Escapes
    My juvenile black and white tegu escaped his enclosure and got outside I've checked absolutely everywhere even pulled up…
    19 August 2020
  • Breezey
    Re: What to do if Your Reptile Escapes
    Our monitor lizard escaped this afternoon. We were really worried and looked everywhere in the house. The window was…
    18 August 2020