Reptile & Amphibian Forums

While I wouldn't ever say anything negative about the work that has been done by any of the people you mentioned, also having been in the rep world for quite some time, I remember there was a bias to lizards in those days that they needed to have supplements. Hl's feed a well rounded diet of mostly ants will do excellent in captivity if all the other husbandry issues are met. I know that you've spent alot of time with respect to Horned Lizards, we both know that the majority of scat studies show that most of the hl's eat a very one-sided diet of ants. I know the scat I've seen on my father-in laws property is San Antonio fro Texas horned lizards is 90% or more ants. I know that horned lizards are opportunistic and will scoop up a moth or soft spider in a heart beat given the chance. But before you make comments about Lester I think his work is fantastic, and he's worked with many different species. He is very knowlegable, and having worked with pacifics, I feel that lESTER IS RIGHT. I've raised newly hatched babies to 3 inches with no supplements. I have had desert and also short horned lizards, and there is nothing wrong with feeding them a supplement, given the right husbadry and lighting, all of these lizards will thrive with or without supplements. And yes this is a forum of opinions, and so now you have mine, and I don't think Lester is off at all. Thanks

From talking with Lester my comment that he works mainly on p. coronatum is correct(a little work is done with platyrhinos and modestum personal comunication). Lester doesn't need to supplement because he offers the HLs the variety of their natural diet, most people don't have the time or resources(they don't visit the HLs natural habitat to collect its diet they buy it).Were you able to raise captive bred HLs from hatchling to adult under articial conditions long term without the supplementation? If you keep them outdoors regularly(natural sunlight) and offer them the variety insects and ants of their natural diet of course you wouldn't need to supplement. I have raised a great number of hatchlings and unless you give them exsposure to sunlight and offer the varities of their natural diet you will run into problems without supplements. Non-movement of limbs, soft toes and digits, improper use of the reproduction organs I'm talking after keeping the HLs under artificial conditions for years not months and not just to 3 inches. I know you can over supplement, but once a week doesn't seem to have any negative effects. Your comment that texas HLs eat 90 % ants is incorrect. Here are the scientificly proven numbers:
Asio 31%
Braconnieri 49%
Cornutum 61%
Coronatum 45%
Ditmarsi 11%
Douglasi 60%
Hernandezi 60%
Mcalli 78%
Modestum 66%
Orbiculare 45%
Platyrhinos 57%
Solare 88%
Taurus 61%
source (Montanucci 1989 The relationship of morphology To diet in the horned lizards genus phrynosoma)

Hello Jeff. I have raised HLs from hatching to 9 years in artificial lighting with and without supplements and not had any problems with malformation or defects. Diet, temperature and lighting were the key factors. To negate Reptoman's observation of scat content of ants of Texas HLs at over 90% is incorrect. Your presentation of Montanucci's information lacked the reference of stomach content analysis. Stomach content analysis of preserved specimens is only part of a dietary study. Stomach content analysis is a "snapshot" of a point in time of what an animal is eating. It may show the ingestion of some insect that may not have chiton segments/exoskeleton that would not show in scat analysis. Scat analysis is a complete cycle of ingestion-digestion-excretion and lends to the most accurate dietary analysis. Scat analysis, just on the Coast Horned Lizard, Phrynosoma coronatum (from 7 different sites over 5 years and 5230 scat) yields a 92% ant requirement. That number is well above a stomach content analysis as presented. Lester G. Milroy III

Hi Lester,
I apologize if I'm coming off as an argumentive know it all, I just see things a bit different. The gut contents in the study were an average of many different specimens (214 coronatum examined, 351 cornutum examined) taken from many different localities, through many different times of the year, through many different years. I wouldn't call that a snapshot. I would also say the gut contents are a much more accurate assessment of the diet than a scat. Ant exoskeletons don't digest while that of soft bodied insects does (what looks to be a fine powder in the scat). In the scat your more apt to see all ants but its not that the HL ate all ants its just that the other insects were digested to a much more finer degree.

I have 4 p. platyrhinos eggs ready to hatch and was thinking of doing a forum study for diet. The hatchlings will be divided separately A,B,C,D (each in a 20 gallon long) and kept under identical temperatures and lighting. Hatchling A will be fed a diet of strictly ants no supplements. Hatchling B will be fed ants and mini mealworms no supplements. Hatchling C will be fed ants and small crickets no supplements. Hatchling D will be fed ants and small crickets with supplements. I will post the weights monthly. This may help determine certain benefits and methods.
Regards,
Jeff

Sounds like a very interesting proposition Jeff. Would 4 individuals be enough to make a very valid study?
There could be growth variations that are normal that could skew the results. A group of 4 may not be enough to get past that variation.

Would it be a more accurate test to do two and two?

Two feed all ants.
Two fed 50% ants, 50 crickets/worms with supliments. (or some similar %).

What are all the parameters you could measure?
Length, weight, ????

Pardon my intrusion in your experiment. It does sound like it would be a cool test.
Cheers!
Cable

Hi Cable,
It would definitely be better to have 4 groups with 4 hatchlings in each. Two males and two females in each group, in raising hatchlings in the past females grew a little faster than males so the sex could definitely be a factor. More numbers would be better but I won't have that many hatchlings this year.

Bertrand Baur has recommended this formula in addition to weight and length in an e-mail:

"Years ago I started to calculate the bodyweight / snout-vent relation. It is difficult to estimate this, because weight has a cubic growth, SV-length a linear one. I saw that the following formula brings good results as far asthe number remains almost the same all over the whole life of a healthylooking animal. Of course the result for the different species is different.
The lowest for P. modestum, the highest for P. ditmarsi and P. taurus. Ingeneral the males have a lower number, because they are more slender, butthis is not so evident because I am calculating with the SVL. The males havea longer tail and the base is enlarged. The formula is: the cube root of the
weight in grams, divided by the SVL in mm, multiplied by 1000. An example: The female P. taurus is 28.6 grams, the cube root is 3.058. Divided by SVL 65mm is 0.047048. This not well readable, so multiply by 1000 and the number is 47.04. This is a very high number, P. platyrhinos, P. mcallii and others have number below 40, even with only 35.0 they are still healthy. The number
for the newborn P. taurus was only about 36, the adult female had about 43-45. So I new that the newborn were a bit too light. But they recovered in a few days. It was also interesting to see that they fed already from the first day on, while the young of egg laying species kept hidden for a few days without feeding. The mother of the young, which was gravid, fortunately, had a number which was the same as the one for the female which was not gravid. It fed well and I could feed queen-ants, which is probably the best food for horned lizards, but it also had to feed the young min her body. I was very happy to see the 13 (6.7) young, running around in the terrarium and all of about the same weight. I separated them from the mother, because a P. ditmarsi once has eaten a newborn two days after birth."