By Richard Lunsford. This question is very common & controversial. We have neither the controlled scientific research nor a narrow enough focus to definitively answer.Terrifying sex organs of male turtles – Tetrapod Zoology. Popular culture would have it that turtles are weak, flaccid, crappy organisms with dull social lives, stunted and barely functional internal organs and – it goes without saying – undersized sex organs. Last warning. Ok, here we go. To begin with, I have to confess that I actually know very little about the subject I’m writing on, and this is despite a reasonable amount of literature- based research. I have also never dissected a turtle, nor manipulated a live turtle’s genitals, so if you know more about the subject than I do, and/or have any amusing anecdotes or personal adventures you’d like to relate, please do feel free to chip in. Hydraulic intromittent male sexual organs – or dicks – are not unique to mammals among tetrapods, but are also present in squamates, archosaurs and turtles, and this phylogenetic distribution has led some authors to conclude that these organs were present in amniote common ancestors. However, in their details, the organs of these groups are all quite different and actually formed from non- homologous tissues. As shown by Kelly (2. The turtle organ, for example, contains only one vascular erectile body and develops on the ventral surface of the cloaca, whereas the mammal organ contains two erectile bodies and is derived from non- cloacal tissue . VS = vascular space; TM = tensile membrane. Note how different the organs are in their cross- sectional structure? The reason is that this might not be the right word to use, though this does depend on who you ask. According to one school of thought, . Isles, pers. Not everyone goes along with this: some biologists who have published on intromittent organs consistently term all of these organs penises (e. Kelly 2. 00. 2, 2. Mc. Cracken 2. 00. For what it’s worth, I personally prefer to restrict . The single erectile body of the turtle phallus is divided into a collagenous corpus fibrosum and a highly vascularized, expandable corpus spongiosum.
As a turtle’s phallus inflates, its length may increase by nearly 5. A 5. 0% increase in length doesn’t sound too impressive, so I assume that even an uninflated phallus – tucked away inside the cloaca – is large. However, the corpus fibrosum increases in length somewhat as well, and hence may contribute to the total length of the erect organ. More on the issue of size in a moment. A pair of long retractor muscles extend for most of the length of the phallus’ dorsal surface, and attach within the body cavity to the lumbar vertebrae. When at rest, the phallus is actually doubled up on itself within the cloaca, and it is the contraction of the retractor muscles that causes the phallus to un- double and protrude (Gadow 1. Bishop & Kendall (1. However, while the mammal penis only has one layer of long- axis fibres, and one layer of perpendicular fibres, the walls of the turtle phallus exhibit multiple layers of these fibres. This array of stiffening collagenous fibres is still, however, highly similar in turtles and mammals: a fact which led Diane A. Kelly to title her 2. The strong similarity observed in the erectile organs of these phylogenetically disparate groups indicates that there are few functional solutions permitting the evolution of cylindrical, inflatable intromittent organs (Kelly 2. Oh my eyes how they burn. What gets me is the funny vocalisations the male turtles make while in the act. Turtles of New York. Many cultures tell fascinating tales about turtles. Several North American Native tribes speak of a great turtle floating in a primal sea, before. Intro: How to Clean a Turtle. So, by some method, you have come into the possession of 1 or more legally edible turtles. Congratulations! They are legendarily good. Kelly is well known for her previous work, widely reported in the media, on penis anatomy in armadillos (Kelly 1. Tallahassee, Florida. Note that the title of Kelly’s 2. It is to be avoided at all costs, for reasons that I don’t need to elaborate on, I’m sure. Anyway, her publications can be obtained, free, from her homepage here. As interesting as it is from the point of view of embryology, phylogeny and microanatomy, what is particularly eye- opening (no pun intended) about the turtle phallus is how frighteningly large and formidable it is in some species. Again, I can’t pretend to have much useful experience in this area, so do help out if you know more. From the images I’ve seen, it seems perfectly normal for some tortoise species to have a phallus that is half the length, or more, of their plastron. I would guess that in a tortoise with a total length of 2. Look at the images accompanying this article, some of which show better- endowed species/individuals than others. The organ is always dark – grey, purple or blackish – with an expanded head and a sharp spine at its tip. To date I’ve only seen the organs of testudinids and emydids, and would like to know if other turtles are the same in these respects. While it might seem like a bloody stupid question, one has to wonder exactly what it is that turtles do with these sometimes enormous organs. As in other tetrapods that sport proportionally large sexual organs (including certain ducks, cetaceans and, yes, some primates), observational data suggests that turtles might employ their members in display or aggression. Honda (2. 00. 1) had this to say about captive specimens of the box turtle Terrapene carolina. Usually while bathing or drinking, the turtle will submerge the front half of his body, rise up on his back legs, and drop his organ through the cloaca. It is a sight to behold, and one that can startle both novice and experienced herpetoculturalists alike. The organ itself is large in proportion to the turtle, and dark purple in color. After several seconds, the turtle will retract the organ back through the cloaca. It may repeat this process once or twice. I also note the title of a very interesting paper by de Solla et al. Unfortunately I have yet to see this paper (a pdf doesn’t seem to be available), so I don’t know if they concluded whether defensive or displacement behaviour better explained the phallus displays they reported. Please let me know if you know the answer (or, even better, can send me the paper). Without information to the contrary, I cannot help but imagine that some turtles might be in the habit of intimidating enemies with their erect 2. Now there’s a thought. You might never look at a turtle the same way again. For previous posts of mine on turtles see the series on snappers and alligator snappers here and Tortoises that drink with their noses. More on turtles in the near future, including stuff on Gilbert White’s pet tortoise, J- Lo the araripemydid and pleurodire diversity, and meiolaniids. So, tomorrow (Monday) is the big day. Action of formalin and histamine on tension and potential curves of a striated muscle, the retractor penis of the turtle. American Journal of Physiology 8. Solla, S. R., Portelli, M., Spiro, H. Penis displays of common snapping turtles (Chelydra serpentina) in response to handling: defensive or displacement behaviour? Chelonian Conservation and Biology 4, 1. Gadow, H. Remarks on the cloaca and on the copulatory organs of the Amniota. Philosophical Transactions of the Royal Society of London B 1. Honda, M. Chelonian notes. Art Journal 6. 0 (2), 9. Kelly, D. Axial orthogonal fiber reinforcement in the penis of the nine banded armadillo (Dasypus novemcinctus). Journal of Morphology 2. The functional morphology of penile erection: tissue designs for increasing and maintaining stiffness. Integrative and Comparative Biology 4. Turtle and mammal penis designs are anatomically convergent. Proceedings of the Royal Society of London B 2. Suppl 5), S2. 93- S2. Mc. Cracken, K. The 2. Argentine lake duck (Oxyura vittata). The Auk 8. 20- 8.
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