Watch Wood Frog eggs become froglets in this NatureNorth Critter Video!
Raising Wood Frog tadpoles is easy!
At Nature North, we practice what we preach. So we've been raising Wood Frog tadpoles, partly to show you how easy it is to do, but mainly because that's just what we like to do! Frog-Log is a record of the tadpoles we raised in 1997. We posted the progress of our tadpoles along with some pictures we took as they grew. It turned out to be a great record of the whole process, so we're leaving it up. If you're raising tadpoles, you can use this article as a reference guide. Just don't assume that your tadpoles will look the same at the same age as our's did. In nature, things do tend to vary!
We've also managed to get a number of Winnipeg Schools into the frog rearing spirit. At Sargent Park School , 13 class rooms (Nursery through Grade 4, the computer room, plus the Grade 8 math and Grade 7 Science rooms) raised wood frog tadpoles in 1998. There were 9 tanks full of tadpoles at Strathmillan School, 2 in Chapman School, 2 in Heritage School, 3 in Hedges School and 3 in Crestview School! Nature North supplied the tadpoles and rearing instructions, and the schools purchased small aquariums for each class room.
(Click links to see images!)
- April 27
- Frog-Log 1997 began when we caught 4 adult
wood frogs at a pond near
the Winnipeg International Airport. Turns out we got 2 male and 2
female frogs. We put them in an indoor aquarium and the males spent
the night calling!
- April 28
- By morning there were 2 pairs of frogs in amplexus - where the male
grasps the female and holds on until she lays her eggs. By doing this
the male is in the perfect position to fertilize the eggs as they
- April 29
- Both pairs were still in amplexus, no eggs
- April 30 [Eggs laid!]
- The first female laid her eggs overnight and the second one laid her eggs around 11:00 a.m. The egg
masses are about 5 cm wide. Each one contains about 500 eggs! Each
egg is about 2 mm across, surrounded by a ball of clear jelly about
7 mm across.
- May 1
- The eggs are still just round black
balls today. The temperature in the aquarium gets to about 22
C during the daytime when the aquarium light is on and drops to about
17 C overnight.
- May 2
- The eggs are changing rapidly, they are now
clearly tadpole shaped blobs!
- May 3 [Eggs hatch after 3 days.]
- The eggs hatched today, most of them by late afternoon. The second batch was hatching
about 6 hours behind the first, about the same delay as when they
were layed! The tadpoles are about 8 mm long. Most of them are just
hanging on the old egg mass or on the aquarium glass. They wriggle
around once in a while.
We took the adults back to the pond where we got them and released them today.
- May 4
- The tadpoles are still just lying or hanging around. No sign of them feeding yet.
- May 5 [Tadpoles = 2 days old.]
- The tadpoles are about 10
mm long now. They are moving around a lot now, but still don't
appear to have started feeding yet.
- May 6
- Took the tadpoles to Sargent Park School today,
all 11 tanks with about 15-20 tadpoles in each. Transported them in
a bag with all the stuff they'd need in the tank.
Did a brief introduction for all the teachers and helped them get
things set up.
- May 9
- The tadpoles are up to 13
mm long today. They've been munching actively since May 7. They're
swimming around a lot now, they burst off when the tank is bumped.
Our tadpoles are in a 15 gallon aquarium. Even so, we have begun to
thin out the population by removing some tadpoles and placing them
in a large plastic pool kept outdoors. With the cooler temperatures
these tadpoles will develop at a slower rate.
- May 12 [Tadpoles = 9 days old.]
- The larger tadpoles are as much as 15
mm long. They are all actively swimming and eating well now, they
shredded several lettuce leaves over the weekend. They are now able
to control their buoyancy and can stay suspended in the water instead
- May 14
- The tadpoles are up to 19
mm long. Some have been gulping air at the surface. Maybe this
is part of how they maintain their buoyancy.
- May 16
- The larger tadpoles are now as much as 23
mm long. Their bodies are getting quite robust now, some are 6-7
mm wide. There are some tadpoles that are much smaller than the rest.
Perhaps they are losing out in the competition for food. Thinned out
the indoor tank again by removing about half the tadpoles again. There
must have been about 1000 tadpoles hatched from the 2 batches of eggs
we had. Now the outdoor pool is getting crowded! Might have to take
some back to the pond.
- May 20 [Tadpoles = 17 days old.]
- The larger tadpoles are up to 28
mm long now! You can see their coiled guts quite well when you
get a look at their undersides. I think there are the beginnings of
hind limb buds appearing beneath the skin at the base of the tail.
- May 23
- The larger tadpoles are now 31 mm long. In
this picture of the underside of a tadpole you can see various internal organs and other structures.
The tiny rod-like structures extending out from the body at the base
of the tail (left side of image) are hind limb buds. The well developed
"beak" or horny jaws (right side of image) are for rasping away at
food. In the center is the long coiled gut and the small round shape
to the right of the gut is the heart. [This photograph was taken
by gently squeezing the tadpole against the aquarium glass with another
pane of glass. In this manner the internal organs of the tadpole are
readily visible. I was able to watch the heart beating and the beak
- May 27
- The tadpoles are as much as 35 mm long. Note
the well developed mouth on this tadpole. Their eyes and the shape of their heads is starting
to make them appear more "frog-like".
- May 30 [Tadpoles = 27 days old, 30 days since eggs laid.]
- These tadpoles just keep on growing! The biggest
are up to 38 mm long. There is a lot of difference between the largest
and smallest tadpoles in the aquarium, with the smallest being 1/2
the size of the largest. But the smallest ones are still larger than
any of the tadpoles kept in the outdoor pool. The individual tail
muscles are visible in a chevron-like design.
- June 3
- The tadpoles are really robust now. The largest
is about 43 mm lg. The hind limbs are now clearly visible, though still small.
- June 6 [Tadpoles = 34 days old]
- The largest tadpole is about 50
mm lg. The hind limbs are growing rapidly now. No sign of fore
limbs, though. Visited Sargent Park School today. Some of their
tadpoles are ahead of mine! That's probably because the classrooms
are warmer than the basement where my tadpoles are.
- June 12
- A 57
mm long tadpole dwarfs another from the outside pool. Cooler temperatures
and more competition for food have resulted in this great size and
developmental difference. Remember these tadpoles are both the same
- June 16 [Tadpoles = 44 days old]
- Things are really cookin' now! It's amazing
how fast these guys go from being big tadpoles with legs to small
frogs with tails. The first of mine have popped front legs. In the
one pictured here you can see the bulge where its forelegs will soon push through. At Sargent Park School
they've had some nearly complete their transformation! That's egg
laid to frog in 47 days!
- June 19 [Tadpoles = 47 days old]
- All of my indoor guys are now froglets
with tails. Today was the first day one of them crawled up onto
the wooden island in the tank. It actually seems that the smaller
tadpoles are transforming ahead of the larger ones; the first out
of the water has a body length of only about 12 mm, not including
tail. The longest any of them got to, as tadpoles, was about 60 mm.
They're all shrinking now as they resorb their tales as food for their
- June 23 [Froglets = 51 days old, 54 days from eggs laid to froglets!]
- My indoor aquarium is full
of froglets now! The largest have a body length of about 18-20
mm. They spend most of their time sitting on the little islands, but
jump off into the water if I disturb them.
- June 25 [Froglets = 53 days old]
Well, that's it for Frog-Log '97. My little froggies are going back to the wild today after some final posing. Sargent Park School held a special "frog release" at Bluestem Nature Park along Omand's Creek in Winnipeg yesterday (back in 1997!). Did you see us on CBC and CKND TV? We were the "happy-news" item at the end of the news casts! Thanks, Sargent Park School, for being a part of Frog-Log. Would your school like to try it out next year?
Thanks for checking out our Frog Log. Bye for now!
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