Another day and another big leap forward for the tadpoles. The gills have developed more and many are now able to swim around freely and strongly. Another big change is in the feeding. Some have abandoned the leftover spawn jelly and are feeding on algae at the edge of the bowl:
If raising some spawn at home to protect it from being eaten or from frosts, now is a good time to release the free swimming tadpoles in the pond.
The tried and trusted method is to transfer the free swimming tadpoles and some of the water from their container to a plastic bag. (much like fairground goldfish). Seal the top with air trapped above the water, place the bag in the pond water out of direct sun for an hour or so, if you have a big pond tether it..
This is done as there can be a big temperature difference between the bowl water and pond and this method makes sure the water the tadpoles are in adjusts slowly to the pond temperature. Just pouring them straight in the pond might result in deaths from temperature shock.
Time now to move the tadpoles to very shallow trays, I bought some new ones that are quite big and just right, for £1 each this morning. (I was so chuffed to find them and such a bargain price too)
If growing them on in trays now is the time to think about providing food. Most of the jelly will be eaten up and they will feed on whatever algae is growing in the water.
However they need more food.
At this stage the tadpoles are vegetarian, the best way to provide food is to chop up some lettuce, boil it for 10-15 minutes and liquidise it.
A few drops are added to the water just to give it some colour, not too much. More is added only when the water clears. One can make up a batch of it and freeze it in ice-cube trays. Defrosting a cube for future feeding when needed.
A new change is happening to the tadpoles. The external feathery gills are disappearing. A fold of skin called the opercullum is growing and covering the external gills. The external gills will then be reabsorbed by the tadpole, which will begin to breath with new internal gills. In the picture one set of external gills are already covered, soon the other will be too. It is difficult to see in the picture, but the tadpoles have faces now, with eyes visible.
Gemma, I'm loving these updates, must remember to show them to my girls. I'm desperately wanting to get hold of some frogspawn to show this to my children as i used to do, but don't know if I'm allowed. One parent even thought you had to have a license to move frogspawn. is this the case. Would I be able to borrow some and release it back into the same pond ?
Was going to write about a newt I found in school pond but will put that as a separate thread so as to not hijack this one too much. Thanks for these updates.
You don't need a license to move frog spawn. You should though seek landowner permission before taking it from a pond not on your own property. It is fine to collect some and release them back at the same pond later.
Now the external gills are gone, they are breathing with internal gills (still no lungs developed yet, that will come in time). They now look like the classic tadpole:
At this stage they are still vegetarian and being fed boiled lettuce.
Looking very closely at the left-hand side of the tadpole a small opening can be seen. This is where the operculum (flap of skin) has not completely grown over. This leaves an opening called the spiracle. It exists to help water to be ejected from the internal gills.
Been searching for a good image on the web to explain the spiracle - I've always found it odd that tadpoles are no quite symmetrical.
Found this illustration which shows the arrangement of the internal gills on the right hand side and spiracle on the left. I always find it hard to explain it in words.
Not much change externally for the tadpoles, but things are going on inside them!
Watching carefully some are now coming up to the surface and taking tiny gulps of air. They have had lung 'buds' for a while, but now they are starting to develop into the proper lungs they will use when they are adult frogs.
If you are rearing tadpoles at this stage it becomes noticeable that they are not all born equal. Some are obviously larger, most are medium sized, some seem tiny.
It is not quite as simple as their genes make them that way. Something, that to me seems almost a little sinister, is going on.
The largest tadpoles are secreting chemicals into the water to suppress the growth of their siblings.
There are lots of theories as to why (and more than one chemical mechanism has been identified), but keeping the others down, lowers the competition that the larger tadpoles have to face, so they can get even bigger at the expense of all the others.
With captive rearing the general aim is to produce as many froglets at the end as possible, in the hope of starting a population or maintaining an existing one. We want to avoid just having one very big tadpole at the end of the process. We want lots in the hope that at least a few live to become adults.
The easiest way to help them is to segregate them. With three trays or bowls, one can be for large, one for medium, one for small.
It will always work out there are plenty of medium ones and less large and even less really small. This works well. The mediums won't affect each other much, the tiny ones will get on better with less competition in their own tray. The bigger ones are best kept away from everyone else apart from ones that are around the same size, because sooner or later they will start to get a taste for meat and an obvious source that is available is the smaller tadpoles.
It can take ages to separate them all out, catching each one in a small net and placing them in different trays. There is a massive benefit for the tadpoles though in doing so. Each tray they are moved to should have fresh rain water, and thus be free of any chemicals secreted by the larger tadpoles.
If you can get the kids doing it they will love it. Not only the netting of the tadpoles, but also deciding which go to nursery, which go to primary school and which are bruisers that need to be in secondary school.
Posts
Still feeding on the remaining jelly. Gills have developed and look more 'feathery'
Another day and another big leap forward for the tadpoles. The gills have developed more and many are now able to swim around freely and strongly. Another big change is in the feeding. Some have abandoned the leftover spawn jelly and are feeding on algae at the edge of the bowl:
If raising some spawn at home to protect it from being eaten or from frosts, now is a good time to release the free swimming tadpoles in the pond.
The tried and trusted method is to transfer the free swimming tadpoles and some of the water from their container to a plastic bag. (much like fairground goldfish). Seal the top with air trapped above the water, place the bag in the pond water out of direct sun for an hour or so, if you have a big pond tether it..
This is done as there can be a big temperature difference between the bowl water and pond and this method makes sure the water the tadpoles are in adjusts slowly to the pond temperature. Just pouring them straight in the pond might result in deaths from temperature shock.
Time now to move the tadpoles to very shallow trays, I bought some new ones that are quite big and just right, for £1 each this morning. (I was so chuffed to find them and such a bargain price too)
https://www.youtube.com/watch?v=HMaVA44-kis
If growing them on in trays now is the time to think about providing food. Most of the jelly will be eaten up and they will feed on whatever algae is growing in the water.
However they need more food.
At this stage the tadpoles are vegetarian, the best way to provide food is to chop up some lettuce, boil it for 10-15 minutes and liquidise it.
A few drops are added to the water just to give it some colour, not too much. More is added only when the water clears. One can make up a batch of it and freeze it in ice-cube trays. Defrosting a cube for future feeding when needed.
A new change is happening to the tadpoles. The external feathery gills are disappearing. A fold of skin called the opercullum is growing and covering the external gills. The external gills will then be reabsorbed by the tadpole, which will begin to breath with new internal gills. In the picture one set of external gills are already covered, soon the other will be too. It is difficult to see in the picture, but the tadpoles have faces now, with eyes visible.
Gemma, this is quite fascinating... Thanks so much for posting these photos.
Gemma, I'm loving these updates, must remember to show them to my girls. I'm desperately wanting to get hold of some frogspawn to show this to my children as i used to do, but don't know if I'm allowed. One parent even thought you had to have a license to move frogspawn. is this the case. Would I be able to borrow some and release it back into the same pond ?
Was going to write about a newt I found in school pond but will put that as a separate thread so as to not hijack this one too much. Thanks for these updates.
You don't need a license to move frog spawn. You should though seek landowner permission before taking it from a pond not on your own property. It is fine to collect some and release them back at the same pond later.
Now the external gills are gone, they are breathing with internal gills (still no lungs developed yet, that will come in time). They now look like the classic tadpole:
At this stage they are still vegetarian and being fed boiled lettuce.
Looking very closely at the left-hand side of the tadpole a small opening can be seen. This is where the operculum (flap of skin) has not completely grown over. This leaves an opening called the spiracle. It exists to help water to be ejected from the internal gills.
Been searching for a good image on the web to explain the spiracle - I've always found it odd that tadpoles are no quite symmetrical.
Found this illustration which shows the arrangement of the internal gills on the right hand side and spiracle on the left. I always find it hard to explain it in words.
Not much change externally for the tadpoles, but things are going on inside them!
Watching carefully some are now coming up to the surface and taking tiny gulps of air. They have had lung 'buds' for a while, but now they are starting to develop into the proper lungs they will use when they are adult frogs.
If you are rearing tadpoles at this stage it becomes noticeable that they are not all born equal. Some are obviously larger, most are medium sized, some seem tiny.
It is not quite as simple as their genes make them that way. Something, that to me seems almost a little sinister, is going on.
The largest tadpoles are secreting chemicals into the water to suppress the growth of their siblings.
There are lots of theories as to why (and more than one chemical mechanism has been identified), but keeping the others down, lowers the competition that the larger tadpoles have to face, so they can get even bigger at the expense of all the others.
With captive rearing the general aim is to produce as many froglets at the end as possible, in the hope of starting a population or maintaining an existing one. We want to avoid just having one very big tadpole at the end of the process. We want lots in the hope that at least a few live to become adults.
The easiest way to help them is to segregate them. With three trays or bowls, one can be for large, one for medium, one for small.
It will always work out there are plenty of medium ones and less large and even less really small. This works well. The mediums won't affect each other much, the tiny ones will get on better with less competition in their own tray. The bigger ones are best kept away from everyone else apart from ones that are around the same size, because sooner or later they will start to get a taste for meat and an obvious source that is available is the smaller tadpoles.
It can take ages to separate them all out, catching each one in a small net and placing them in different trays. There is a massive benefit for the tadpoles though in doing so. Each tray they are moved to should have fresh rain water, and thus be free of any chemicals secreted by the larger tadpoles.
If you can get the kids doing it they will love it. Not only the netting of the tadpoles, but also deciding which go to nursery, which go to primary school and which are bruisers that need to be in secondary school.