Confused Frogs?

[Broch]

On the 18th February, exactly one year to the day after last time, the frogs started their annual orgy in our pond - too many to count. Then we had the snow and ice last week and, I presume, most of the frog spawn will have been killed off with the exception, perhaps, of the parts deepest in the water.

Today, after the ice has finally cleared from the pond, they're back - full on orgy again! I don't recall ever having two separate episodes before.

 

[Robson Valley]

Several species do that in the event of a reproductive failure. They can "turn it on."
Well done to notice. Have you been able to find any evidence of living & developing frog embryos
that would have started before your cold spell? Pond water is a great insulator. How thick was the ice?

Most of the time, the second event goes un-noticed. Here, cow moose will go into estrus
about a month after the usual rut, if they are not pregnant already.

 

[Broch]

Several species do that in the event of a reproductive failure. They can "turn it on."

I had heard of mammals going into a second 'season' but I have never noticed frogs doing this before. After all, they had all dispersed, so how did they 'know' the process had failed. The truth is, of course, they probably didn't. I suspect they are just engineered to react to 'false' springs or second springs following a freeze.

The ice was about 75 to 100mm - not deep I know but the area they lay in every year is full of weed so the spawn tends to sit high in the water.

It now looks like we have dead spawn (when it turns milky white), developing spawn (larger embryo development on the lucky deeper original lay), and a new mass of fresh spawn.

 

[daveO]

At least the survivors should have a feast when they hatch. The only spawn I've seen up here so far was in a shallow but flowing ditch. I haven't been up there since the snow though to see how it got on. It might still be buried. My pond is still a foot or so under the snow.

 

[Robson Valley]

Thanks. This is very interesting. So. Probably some die off.
The variety which could not double spawn is likely extinct or headed in that direction.
Just think of the huge reserve of nutrients needed to "go 'round again!" Super-frogs.
At least in the beginning you get 2 size classes of tadpoles.

We have a nondescript amphibian salamander which spawns in standing ditch water.
It's so early in our spring that they must be shaking snow off their gonads. The fertilized eggs are 10mm in diameter and attract
a coating of flocculant debris = basically invisible. Takes a little poking around with a twig to get a couple to roll.
How the adults avoid a frost death is a puzzle (burrow in the mud like frogs?)

 

[daveO]

How the adults avoid a frost death is a puzzle (burrow in the mud like frogs?)

Some amphibians make their own antifreeze but I don't know if that applies to your salamanders. Frogs are suprisingly tough and adaptable though. I've had tadpoles in one of my ponds that didn't bother changing into frogs and stayed as tadpoles for an extra year. I'm not sure what caused that but they had a good headstart the following year.

 

[Robson Valley]

Probably some common characters among all of the amphibians. Good way to wait it out when there's no food/bugs.
I believe that there are some frogs with normal 2-year tadpole development. I really was an undergraduate jerk.

Leopard frogs will metamorphose from tadpoles one at a time under very crowded conditions.
Some kind of secretions win the competition for resources.

I think that learning a pond, studying the same one every week, you see things that single visitors are bound to miss.
There's a short stretch of a local river that I've always tried to stop at for 10 minutes and have a good look both up and down stream.
It changes like it's breathing.