Sexual Size Dimorphism

[Gio]

This is an old but very interesting study.

https://www.researchgate.net/publica...mbat_in_snakes

It is worth reading and may clear up some misconceptions surrounding male and female sizes in certain species of snakes.

Often, it is automatically assumed that female snakes are always larger than males. While it is true in many situations (even in some combative species) there are certain species where males are equal to or larger than females.

This study is worth a read.

I have had the pleasure and privilege to speak with Nick Mutton on several occasions about his field observations.

Carpet python groups that engage in male combat prior to mating can and do produce large males in the wild. Nick also mentioned the same often occurs in reticulated pythons.

Captivity can change things, however it is often based on a keeper not wanting to have large males to feed and deal with.

The main point is that it is wrong to assume just because somebody buys a male animal it will stay small or always be the smaller of the two sexes.

Genetics, feeding, environmental, or in the case of captive animals, husbandry all play a role.

Snakes are difficult to study in the wild and funding does not always exist but I thought this was an informative link.

I hope it generates some discussion.

I have a male Bredli that is getting pretty large, and my male boa which is not a combative species is getting larger with age. The largest snake outside of a male retic I owned was my late female, coastal carpet.

Unfortunately I don't have two animals that are both the exact same species so I can't share my captive experiences regarding size.

If anybody does have two or more of the same species that are the same age or close, share your experiences and post some pictures.

[Bogertophis]

In my 2.2 sibling "Florida" rat snakes (Yellow x Gulf Hammock x Everglades?) age 16 years- the males are noticeably larger than the females (7' males compared to 5.5-6' max for females). It's pretty apparent to me that the reason for this disparity is that the females lay large clutches (double clutches, in fact!) every year, so much of their food intake goes for that rather than growth in length & overall size. This is the best example I have, & the only one currently where I have multiple snakes of the same size & age.

In the past, I bred a number of rosy boas, & there the females are significantly larger than the males- clearly the females eat more for reproduction of numerous live neonates. The breeding females were usually around 40" long, while the males reach about 30" max, with a smaller diameter. So it very much depends on the species as to which works better.

[Bogertophis]

And by the way, my female rat snakes are literally "eating machines"- they are fed all they want, all year long.

[Gio]

In my 2.2 sibling "Florida" rat snakes (Yellow x Gulf Hammock x Everglades?) age 16 years- the males are noticeably larger than the females (7' males compared to 5.5-6' max for females). It's pretty apparent to me that the reason for this disparity is that the females lay large clutches (double clutches, in fact!) every year, so much of their food intake goes for that rather than growth in length & overall size. This is the best example I have, & the only one currently where I have multiple snakes of the same size & age.

In the past, I bred a number of rosy boas, & there the females are significantly larger than the males- clearly the females eat more for reproduction of numerous live neonates. The breeding females were usually around 40" long, while the males reach about 30" max, with a smaller diameter. So it very much depends on the species as to which works better.

This is typical for the most part. Although I noticed you said Rosy Boas which I know little about.

I did have a conversation with Gus Rentfro years ago about male boas, (constrictors) specifically kept as pets and he stated male boa constrictors can attain sizes equal to females if they are fed the same, and if the don't go through the breeding season cues that stimulate them to search for a mate. I only have one male boa and he does not sense females here as I don't have any.

Huge boas are not the norm and his view, based on research in the wild was that the oldest boas are the largest boas. It seems like a simple answer but there are factors involved. Boas in captivity are very often and easily overfed and frequently die early never attaining their ultimate size.


Anomalies exist everywhere, however when it comes to male combative species it is far more common to find larger males according to some experts.

In captivity we intentionally and unintentionally change things especially people who are in a rush to breed their animals.

My late female, coastal mix was a good sized animal that was fed conservatively and often she was a picky eater. Somehow she became the largest animal here outside of the male retic I re-homed.

I really miss her.






My Bredli that is really starting to put on size.
These photos are a year or more old.






I'll have to get him out this year to show off his added size.

[Armiyana]

I am the owner of a 2400g male ball python. He is kept lean and is the largest BP in my collection. And a proven breeder so no false ID. Hahah
I always have to point to him when someone says male BPs will never be as large as females.

[Bogertophis]

Gio, your snakes are always amazing!