Hi Henrik,
this is very interesting - thanks for posting. I just discussed a similar issue in summer: http://www.fieldherping.eu/Forum/viewtopic.php?f=10&t=154

For me, the question is: does Zootoca really have socials structures (families? clans?) or are they just less agressive than other lizards? Is thet "brood care" are consequence of being viviparous?

Kind regards
Peter 

Hi Peter,

Thanks for your kind response and for sharing your thread from fieldherping.eu!

I am not certain when Z. vivipara populations to some degree exhibit truely social structures. I presume they are at least not so pronounced.

But in my opinion the behaviour which I observed in the two individuals on the top of the pole indeed appeared as social interactions. But maybe they were together merely to use an excellent spot for basking? I think it was more than that, considering the behaviour where they were close together (which, I think, also appears from my photo series). Including tongue flicking which I, however, did not photograph.

In contrast, when we see e.g. aquatic turtles congregating on branches and logs in and above the water surface to bask, I have so far never seen any real interactions. Sometimes they may compete to get the best basking spots, but that is basically it!

One question is whether the adult female and the juvenile which I photographed, were mother and child. Indeed I do not know. However, I have discussed it with Henk Strijbosch who has made extensive studies of Z. vivipara behaviour. In the field and in the lab. His observations show that it is indeed mother and child which are involved in such social interactions. He concludes that they know and recognise each other which keeps possible aggressive reactions to a minimum.

A bit less than 20% of all lizard species are viviparous. As far as I can judge, it is also approx. 20% of those lizard species exhibiting parental care which are viviparous. However, it may be that a relatively high number of viviparous species with parental care have been ignored, so that their parental care may not have been discovered. That means I suspect that comparatively more viviparous species than oviparous species exihibit parental care.

Parental care in viviparious species is usually carried out by mothers, i.e. as maternal care. In two Australian skinks (Tiliqua rugosa, a very well-studied species, and Egernia stokesii) newborn lizards discriminate between their mothers and other females by means of chemical cues. That has been summarised by Pianka and Vitt (2003, Lizards: Windows to the Evolution of Diversity).

O'Connor and Shine (2004) investigated parental care in another Australian skink, Egernia saxatilis. They concluded that parental care may protect against infanticide:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4DXB91Y-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1124100513&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=8d4ff1cadfec45765ff194e2d0e6be3f

Kind regards,
Henrik Bringsøe 

Oops. sorry about the long link which makes the text difficult to read! Thus, I will repeat the answer WITHOUT the links which will hopefully make it more reader-friendly:


Hi Peter,

Thanks for your kind response and for sharing your thread from fieldherping.eu!

I am not certain when Z. vivipara populations to some degree exhibit truely social structures. I presume they are at least not so pronounced.

But in my opinion the behaviour which I observed in the two individuals on the top of the pole indeed appeared as social interactions. But maybe they were together merely to use an excellent spot for basking? I think it was more than that, considering the behaviour where they were close together (which, I think, also appears from my photo series). Including tongue flicking which I, however, did not photograph.

In contrast, when we see e.g. aquatic turtles congregating on branches and logs in and above the water surface to bask, I have so far never seen any real interactions. Sometimes they may compete to get the best basking spots, but that is basically it!

One question is whether the adult female and the juvenile which I photographed, were mother and child. Indeed I do not know. However, I have discussed it with Henk Strijbosch who has made extensive studies of Z. vivipara behaviour. In the field and in the lab. His observations show that it is indeed mother and child which are involved in such social interactions. He concludes that they know and recognise each other which keeps possible aggressive reactions to a minimum.

A bit less than 20% of all lizard species are viviparous. As far as I can judge, it is also approx. 20% of those lizard species exhibiting parental care which are viviparous. However, it may be that a relatively high number of viviparous species with parental care have been ignored, so that their parental care may not have been discovered. That means I suspect that comparatively more viviparous species than oviparous species exihibit parental care.

Parental care in viviparious species is usually carried out by mothers, i.e. as maternal care. In two Australian skinks (Tiliqua rugosa, a very well-studied species, and Egernia stokesii) newborn lizards discriminate between their mothers and other females by means of chemical cues. That has been summarised by Pianka and Vitt (2003, Lizards: Windows to the Evolution of Diversity).

O'Connor and Shine (2004) investigated parental care in another Australian skink, Egernia saxatilis. They concluded that parental care may protect against infanticide:
LINK OMITTED

Kind regards,
Henrik Bringsøe 

forum_24_232


I don't know if I've done this right, but I've tried to attach a picture of a female and male Sand Lizard and a male Common Lizard all basking together in perfect bliss! 

No Mike, unfortunately your picture was not uploaded properly. But I would really like to see it. For how long did the three individuals bask together? Is there any other information about your observation which you find relevant to add?

I guess you have uploaded it properly and that you can see the icon of your picture under "My photos". Since you have written "forum_24_232" in your answer, I presume this is the code/number of your photo. But that is not fully correct. You will have to use the form "photo()" together with that number, so that the code/number will be in bracket.

I am also new to this forum, so I am not really familiar with all its function. I do not know whether I can add YOUR picture in my answer, but I will give it a try:

Otherwise you will have to do it yourself!

Kind regards,
Henrik Bringsøe 

Success!

I see something green in the background which could be plastic or painted wood. Was your observation made in captivity?

Kind regards,
Henrik Bringsøe 

Well done, Henrik for managing to upload my photograph! The picture was certainly taken in the wild, on the Merseyside coast on 22 July 2007. Although that particular female Sand Lizard was observed frequently that Summer and sometimes with her mate, the male Common Lizard was probably on top of them for only a minute or two, although often nearby. The site was close to some houses and the lizards seemed to be drawn to a discarded root ball of a garden plant which provided a good basking spot in what was otherwise a rather lush overgrown area in such a wet Summer.

Cheers
Mike 

Thanks for the details, Mike.

Considering that you made your observation and photo in midsummer, I imagine that most aggressions and territorial behaviour of the male Sand Lizard had diminished markedly, compared to its habits in spring. Still, it is noteworthy that it proved quite amicable to the smaller Common Lizard.

Kind regards,
Henrik Bringsøe 

Two obviously pregnant females - one lying partially upon the other. A juvenile had just left the rock. Since there are a lot of good basking spots in their habitat, they had no need to be so close. I think they must have wanted to touch each other.

Thomas,
great shot! It would be intresting to wwatch these animals for some day subsequently to see if this was a single contact or a frequent pattern of behaviour. In other words: do they "know" each other?
Regards
Peter 

An interesting photo, Thomas!

We have many indications that the interactions of Z. vivipara have a social character. But we need more quantitative analyses in order to support our various observations. Henk Strijbosch has told me that his extensive material on such behaviour may not be sufficient in terms of statistics. I hope he will publish his results one day!

Kind regards,
Henrik Bringsøe 

An interesting photo, Thomas!

We have many indications that the interactions of Z. vivipara have a social character. But we need more quantitative analyses in order to support our various observations. Henk Strijbosch has told me that his extensive material on such behaviour may not be sufficient in terms of statistics. I hope he will publish his results one day!

Kind regards,
Henrik Bringsøe