Bat development


It always gives a fellow a warm feeling to see an old comrade-in-arms publish a good paper. Chris Cretekos was a graduate student working on the molecular genetics of zebrafish at the University of Utah when I was a post-doc there, and he’s a good guy I remember well…so I was glad to see his paper in Developmental Dynamics. But then I notice it wasn’t on zebrafish—Apostate! Heretic!

Except…it’s on bats. How cool is that? And it’s on the embryonic development of bats. Even cooler! I must graciously forgive his defection from the zebrafish universe since he is working on an organism that is weird and fascinating and important.

Here’s the abstract:

There are approximately 4,800 extant species of mammals that exhibit tremendous morphological, physiological, and developmental diversity. Yet embryonic development has been studied in only a few mammalian species. Among mammals, bats are second only to rodents with regard to species number and habitat range and are the most abundant mammals in undisturbed tropical regions. Bat development, though, remains relatively unstudied. Here, we describe and illustrate a staging series of embryonic development for the short-tailed fruit bat, Carollia perspicillata, based on embryos collected at timed intervals after captive matings. As Carollia can be readily maintained and propagated in captivity and is extremely abundant in the wild, it offers an attractive choice as a chiropteran model organism. This staging system provides a framework for studying Carollia embryogenesis and should prove useful as a guide for embryological studies of other bat species and for comparisons with other orders of mammals.

What this paper is is meat-and-potatoes embryology—it’s a staging series, the kind of paper that documents the pattern of normal development for an organism as a reference. The zebrafish staging series is online, so you can see what one is like; it’s a collection of photos and descriptions coupled to a timeline so that everyone has a standard reference point for future studies.

I can’t say much about the paper. It consists of tables of stages and dry Latin words and lots and lots of photos of embryos, and it’s the kind of droolworthy thing where you just want to look at the pretty pictures. So, here, a few of the figures from the paper.

Of course I have to show you a bat pharyngula. Early development isn’t very surprising—it’s generic mammalian stuff—but here you can see that common appearance all of us vertebrates have early on, looking like a segmented worm with an odd cluster of protrusions at the head end. The glossopharyngeal arch (ga) is marked, as is the otic vesicle (otv) and forelimb bud (fl).


You can start to see some dramatic differences from the human pattern of development at 60-90 days of gestation. Look at those forelimbs; you can see our five-fingered layout there, but there is extensive webbing and the fingers just grow and grow. I love those first couple of shots. The little guy looks so shy, hiding behind those big hands.


These are some closer shots of the developing limbs in 54-70 day old embryos.

a, autopod; aer, apical ectodermal ridge; ca, calcar; chp, chiropatagium; cl, claw primordium; dc, digit condensation; fp, foot plate; hp, hand plate; id, interdigit; mc, metacarpal; pl, phalange; plp, plagiopatagium; prp, region of the propatagium primordium; s, stylopod; tm, thumb; urp, uropatagium; z, zeugopod. All panels show the dorsal surface of the right limb with anterior toward top and the proximal at left, views are not to scale.

A lovely piece of work like this makes me want to open up a few pregnant bats…but on the other hand, I also like to keep our local bats happy and thriving and eating mosquitos. At the very least, though, I hope there is more work on bat embryology coming up soon.

Cretekos CJ, Weatherbee SD, Chen C-H, Badwaik NK, Niswander L, Behringer RR, Rasweiler JJ (2005) Embryonic staging system for the short-tailed fruit bat, Carollia perspicillata, a model organism for the mammalian order Chiroptera, based upon timed pregnancies in captive-bred animals. Developmental Dynamics 233(3):721-738.


  1. Rocky says

    Has anyone run across info that bats are supposedly closely related to basal primates? Love to read any good links….

  2. afarensis says

    Ricky if you have access to Nature check out vol 345 pgs 291-292, 340-344. I think that derives from the idea that tree-shrews, bats, deropterans and primates constitute a phylogentic unit called the Archonta (paper here). At any rate if you google archonta you should be able to find a ton of info…

  3. DAE says

    While fruit bats have tricolor vision and an arrangement of optic nerves similar to primates, the latest genetic research suggests that bats are not true archontans as previously thought. They are a monophyletic clade that sort genetically with the majority of placental mammals in the recently described supraordinal clade of Laurasitheres, including ungulates, basal insectivores, carnivorans and pangolins. The true archontans(Euarchonta)are now restricted to primates, dermopterans and scandentians. They are united with the superordinal Glires, i.e. rodents and lagomorphs (rabbits, hares and pikas) into the clade Euarchontoglires, which probably had an east Asia/southeast Asian origin.

  4. mjfgates says

    A bat becomes a human being at conception! Ban bat abortions, except in the case of bat rape or bat incest! .. um, right.

    Yay, bats!

  5. noahpoah says

    This is pretty much completely off-topic, but I find it kind of fascinating (as a descriptive linguist) and kind of annoying (as a prescriptive linguist) that the structure “what X is is…” has become part of the English language.

    As in “What this paper is is meat-and-potatoes embryology…” in place of “This paper is meat-and-potatoes embryology…”

    That said, bats are the shiznit. Those photos are profoundly beautiful.

    At the ASA conference in NY city a few years ago, I was tired from standing at poster sessions all day, so I looked in the program for some nice, interesting sit-down talks in a field other than my own, and I found a series of talks on the neurology of bat echolocation, as well as an impromptu talk on bat song based on observations of bats rescued by some woman in Texas who has devoted a barn and much time to nursing injured bats back to health (I don’t remember her name). The point is I like bats.

  6. says

    Yes, it’s interesting.. I would be tempted to analyze “what this paper is” as an idiom standing for “the style of this paper” or “the content of this paper” etc. Since “is” would follow either of those two phrases, it also has to follow “what this paper is”. I know someone who often says “The thing is, is that..” which is just like “What’s going on here, is that..”, etc.

    Seriously, check out the bat poster on my link above– the photos are great, very high-resolution and there’s no annoying (but informative) lines across them.

  7. chuko says

    I read the “is is” as a presentation, a quicker way of saying “Take a look at this paper! It’s a meat-and-potatoes embryology…” I’m curious how this corresponds with a linguists take on the construction.

  8. Rocky says

    Thanks for the info above guys!
    I plan to Google each and do some reading.
    Damm, I love this website!