Reptile & Amphibian Forums

Hi Ken,
Once again, thanks for the quick reply.

>>Brighter colors in a more ornate pattern may begin to develop on the head in males.

Magnum has some orangish yellow patches starting to form on his/her head, which might indicate that he/she is a male, although the patches aren't very bright, and overall "he" seems to have the characteristics you mentioned to indicate that he is most likely a she.

>>
>>you may never really be certain until he mounts another turtle or she lays eggs. It's also different between the subspecies. Magnum has coloration almost like a Gulf Coast, but I'm assuming that he/she is an Eastern.
>>

I assumed that Magnum was an EBT when I got him since he was wild "caught" (rescued) and Easterns are the only subspecies of BT that naturally inhabit NJ (that I know of). A customer found him outside of my workplace in the middle of the parking lot. There are no woods surrounding the lot, so we weren't quite sure how he got there. Because he was found in the center of the parking lot (absolutely nowhere to hide) and there are no woods surrounding the area, I wonder if he didn't get there on his own. He was limp and cold and he had no fat on him. I couldn't imagine this weak little guy traveling all the way across the large, open parking lot to where he was found. He could hardly move because he was so cold, and I thought boxie hatchlings were very timid - there would be no reason for him to walk into the open where there were a lot of people, cars and noise and no place to hide.

>>If you know at what temperature the egg was incubated, you can get a percentage chance of the sex.
>>

Because he was a rescue I don't know at what temperature the eggs were kept naturally. He still had his eggtooth when he was found in a parking lot in mid/late October.(I'd assume the egg was kept fairly cool since he hatched so late in the season - Do box turtles usually hatch in the fall or was this an abnormally late "birth"? Are males or females incubated at lower temperatures?).

>>Magnum P.I. hehe, you'll have to paste a fake mustache on him for a good photo-op. Thank you for sharing the pics!

Hahah, that would be so cute! Although, if he is a she, she might be offended Even if it turns out that Magnum is a girl, I can't change the name - She'll just have to accept that she was named after Tom Selleck's character Thank you for replying.

-Lisa
-----
1.0.0 Jack Russel Terrier: Skipper
0.1.0 Miniature Pinscher: Bambi
1.1.1 Eastern Box Turtles: Daisy, Dozer, and Magnum
0.1.0 Red Eared Slider: Rosie
0.2.0 Rats: Clementine and Elsie

Yes, they typically do hatch in the fall. Some overwinter in the nest and emerge the following spring.

In the natural condition, box turtle nests can have very variable temperatures. Eggs near the top of the nest can be incubated at different temperatures than those at the bottom. I'd say that the chance is about 50/50.

That chestnut color is common in Gulf Coasts. I have seen it in Easterns, though. I figured that Magnum was an Eastern...I was just trying to cover all the bases.

Who knows how he got there? Someone once brought me a baby Diamondback Terrapin that they found on the beach. They said that they were feeding gulls, and one gull swooped in, dropped something, and began going for the stale bread. One of their children checked the "rock" that the gull had dropped and it was a baby turtle!! It's amazing, turtles can fly!! Of course, the people assumed that it was one of "those green turtles" that they used to sell at Myrtle Beach. They promised to take the turtle back and release it in the closest bay waters.

We thought that maybe a seagull might have caught him somewhere and then dropped him to crack his shell (they do this with clam shells very often) - Just a guess though - He really could have come from anywhere. Thanks for the reply.
-----
1.0.0 Jack Russel Terrier: Skipper
0.1.0 Miniature Pinscher: Bambi
1.1.1 Eastern Box Turtles: Daisy, Dozer, and Magnum
0.1.0 Red Eared Slider: Rosie
0.2.0 Rats: Clementine and Elsie

Hi again,
I am interested in your mentioning of assessing a percentage of certainty regarding sex based on incubation temperatures. We often have anomalies with other ESD turtles but I have no experience with incubation of EBT eggs. So I am wondering, what is your confidence percentage for eggs incubated at ~ 26 degrees C (78.8 degrees F) and eggs incubated at ~ 29.5 degrees C (85.1 degrees F) (with little variance, perhaps /- 1 degree C or 1.8 degree F).
Thanks!

"So I am wondering, what is your confidence percentage for eggs incubated at ~ 26 degrees C (78.8 degrees F) and eggs incubated at ~ 29.5 degrees C (85.1 degrees F)"

I recently read a publication regarding general box turtle natural history, some aspects of captive care, and techniques for using box turtles in the classroom(figuratively). I actually tried to post it on this site, but it was removed rather promptly. I think it was considered advertising, which is against the terms of service. Here is one table almost exactly as it is given in the text (I had to alter it slightly so that it would fit). Because of the TOS, I won't mention the publication on here again. However, lest anyone accuse me of plagarism, the exact reference is available upon request.

"Temperature-Dependent Sex Determination Study In Controlled Laboratory Conditions*

Temperature........Males hatched.......Females hatched
22.5 OC........................73 %...................27 %
25.0 OC........................96 %....................4 %
27.0 OC........................81 %...................19 %
29.0 OC.........................0 %..................100 %
30.0 OC.........................0 %..................100 %

Controlled laboratory study performed by scientists Ewert and Nelson in 1991. The Eastern box turtle typically
shares the pattern as seen above but the exact pivotal period has not yet been determined (Dodd, C.K., 2001)."

I hope this helps.

That is quite interesting, thanks! I was able to locate said publication on the internet (the one that was removed), so thanks again!
Cheers.