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Category — Waterdog

Waterdog Babies Hatch at CREW

This past summer, CREW‘s aquatic salamander lab welcomed baby waterdogs into the world.  Female waterdogs ‘Glitzy’ and ‘Muffintop’ both layed fertile eggs.  It has been exciting to witness and document the development of these very elusive animals.  It took quite some time before we could see the first evidence of the embryos forming and once they did, it was mesmerizing to watch them develop into full grown waterdog babies.  We were rooting for them all the way to hatching!

This photo shows an early time point in waterdog embryo development. You can see the bodies starting to form around the very large yolk sacs.  As you notice in the photo, waterdog babies lack pigment early in development.

Waterdog Babies

Waterdog Babies

As the babies progressed in their development, they became bigger and started to show evidence of pigmentation.  This video shows early movement in one of the waterdogs while it still resided within the sac.  Waterdog babies need to learn to maneuver while still in their sacs in order to be able to hatch themselves out.  And hatch themselves out, they did!

After hatching, the babies started to get their ‘groove on’ and learn how to move about.  This video was taken right after they successfully hatched and you can see how challenging it was for them to stay upright.  Having such a little body resting on a large yolk sac looks funny, but is totally normal for a waterdog baby.  The yolk sac is very important, as it provides the energy source for the developing babies.  They continue to obtain their nutrients from the yolk sac until they start hunting and eating on their own.

September 20, 2013   1 Comment

Waterdog Eggtravaganza!


Eggs are visible.

CREW’s aquatic salamander laboratory supports the only zoo-based captive assurance population of the endangered Black Warrior waterdog.  In the first year of the project, CREW scientists developed the life support and husbandry protocols necessary to maintain this species in captivity.  In the following two years, we’ve focused more on stimulating successful breeding and reproduction in the waterdogs by administering exogenous hormones and implementing seasonal changes in water temperature and lighting.

In 2012, we had a single black warrior waterdog ovulate and deposit over 50 eggs during three days in April.  This year, we had one Mudpuppy, one Black Warrior and two Gulf Coast waterdogs deposit eggs.  While some eggs were not fertile, eggs from two Gulf Coast waterdogs were fertilized and marks the first report of successful breeding of this species in a zoo setting.  A waterdog eggtravaganza!

Muffin Top with her eggs.

Muffin Top with her eggs.

Pat Story, Cincinnati Zoo’s Media Projects Manager, was able to capture Black Warrior waterdog ‘Scarlet’ in the process of laying her eggs.  As you can see from the video, female waterdogs deposit their eggs upside down on the underside of rocks or logs.  We offer either substrate to our female waterdogs, so they can choose their nest location.

In many amphibian species, there is little maternal investment after eggs are deposited.  However, a waterdog mom puts a lot into ensuring she has a successful brood.  It has been amazing to watch how devoted these females are not only to laying the eggs, but how intensively they guard and brood them (which involves keeping them clean and well aerated).  This process is also quite prolonged; the time from deposition to hatching is > 70 days.  We are excited to show you in upcoming blogs how the larvae have developed and hatched.


July 3, 2013   1 Comment

CREW Waterdogs Have the Right Stuff

Waterdogs exhibit distinct periods of activity and feeding depending on the season.  Reproductive function is also highly seasonal.  Male waterdogs produce spermatophores in Fall, at which time females collect and store the sperm internally for several months before laying eggs in late Spring/early Summer.  Waterdogs are unique among amphibians in that fertilization takes place internally as eggs are being deposited.

Waterdog Sperm

Waterdog Sperm

Using a combination of exogenous hormone administration and seasonal shifts in temperature and lighting we’ve been able to induce spermatophore deposition from male waterdogs housed in CREW’s aquatic salamander lab.  Spermatophores are an organized packet of sperm.  Each spermatophore contains an outer mucoid layer and a sperm rich cap.  We often don’t find the entire spermatophore, but only evidence of the mucoid layer, in tanks where both male and female waterdogs are housed together.  It is believed that the female waterdog takes up only the sperm rich fraction of the spermatophore into her cloaca.  Upon microscopic examination, we’ve measured individual waterdog sperm at over 900 um in length- that is over 18 times longer than the average human sperm cell (which is just a mere 50um)!

Video footage from CREW’s Aquatic Salamander Lab captured the deposition of a spermatophore from a male waterdog named ‘Sugar Bear’. Look closely on the log where the male is residing and you will see the white cap of the spermatophore upon his exit to an adjacent log.  Sugar Bear is the daddy of our soon to be hatched waterdog babies so we know he has the right stuff!

June 10, 2013   No Comments