Soni's picture

Black sack with what looks like blood vessels

Observed: 4th May 2013 By: Soni
What on earth

There were two of these found by the resvervoir on the Denbigh moors. One was slightly squashed as can be seen in the second image, inside apears to be something like intestines with blood vessels. Shiny and dry on the outside and roughly an inch in size. The path was close to an area of marshy ground but also very close to heathland...

Species interactions

No interactions present.


nightfly's picture

Hi Soni, There are a few more

Hi Soni,

There are a few more examples of this on iSpot. Yours is nicely dried on the surface just as the ones I found on Tuesday evening were. Did you check out its consistency? Its like a ball of glue- the ova are held together with the gelatinous coating which becomes the protective jelly spheres around the ova when it is imersed in water.

Just at the moment I cant post an observation due to laptop issues but I have identical pics to what you have above taken just 4 days ago. I'll post and link them as soon as I can.

In this example the ova has had exposure to a bit more moisture as the gelatinous coating has begun to take the water on- its more swollen than in your example:


Soni's picture

Hi Cathal, thank you! Someone

Hi Cathal,
thank you! Someone else has suggested that today but with your description and finds, especially with other frog parts attached is pretty conclusive.

I was thinking along the lines of an indegestable organ, but ovaries hadn't sprung to mind.

Thanks again


dejayM's picture

First post

A really excellent post Soni. EXCELLENT photos, quality description and ID Notes.
Your reward is a prompt ID (Cathal) and a comment Trail.
Keep it up please.
You ought to move the post to Invertebrates - even though they are eggs!

DavidHowdon's picture

Why invertebrates?

surely Amphibians and Reptiles would be correct.

dejayM's picture


yeh, yeh..David. I was hoping I could get home and on-line before someone told me!
Spent the whole day fretting! As you have probably noticed (I hope so) I have Invertebrates on the brain; what brain?!

dejayM's picture

quite right

So, after all this time (and frustration) it seems that if we Add a New ID, it will auto change the Group. That is a helluva blessing IF we add the right ID! I may have done, as I believe Cathal (nightfly) is quite right.

nightfly's picture

Hi Chris and Derek, These

Hi Chris and Derek,

These are a bit frustrating- well the fact that the question, does it actually belong to a toad and not a frog, is ever present and potentially makes my certain frog ID presumptious.

All I can say with certainty is that these objects above are completely inseperable from the remains left when a female frog is eaten. I have umpteen images just like this from lake shores where only frogs are present. No toads in this part of Ireland and most of the rest of it.

What we really need is certain toad examples to see if they look the same. We dont appear to have ceratin toad examples. Until such times maybe my frog ID is erroneous/presumptious, therefore not scientifically sound. We do have so many frog examples, are frogs more widespread and numerous in general in Britain? It would possibly explain the sheer number of certain frog examples of this we do have.

This comment is prompted by the fact that many of these observations may need to be made into frog/toad identifications. That is, if there isnt definite evidence of one animal or the other having been eaten there.


dejayM's picture


Yes, I agree - we cannot be certain about Toads. A 'pack' like this could have been ejected by an animal (or bird) after ingestion. I'd like to think Frog because of the intense packing but eggs INSIDE a toad are presumably packed tightly too.
I think we have made, over the recent year or so, the major points about these occurrences. Anyone coming in the future who does not read SOME of our notes would be foolish.
I do find this pack specially interesting regarding shape - is this the shape the pack would be inside a frog, or have the eggs been packed inside a predator and, either ejected (from one end or the other!) or predated a second time! There's a thought!
I have been off-line for ages, just creeping into my Public Library for half-hour sessions - very frustrating.

nightfly's picture

Hi Derek, This is the shape

Hi Derek,

This is the shape of both packs inside the frog, the egg sacks are paired inside the frog, encased within an extremely thin membrane- the sac. I have many images just like above showing both sacs together just as they are orientated within the frog. This one above is partially air dried. The eggs are bound together within the frog, individually encased in a water absorbant membrane. The membrane becomes the jelly globes around each ova upon immersion in water. The jelly is incredibly glue -like when in the process of taking on water, this quality keeps the egg mass together in the familair clumps, this despite the fact that the eggs are deposited by the frog like a string- they dont remain as a string when in the water as their own stickiness makes them become a large ball- they stay together. Having seen so many discarded egg sacs and dismembered frogs I don't think these are being injested, quite the oppositte -I think they are being very purposefully removed and avoided. Possibly due to the potential for unwelcome size increase within the predator, as has been stated often on iSpot.

I have a very good image from March this year, of both egg sacs together, I will post it now. It shows the nature of the egg sac and one of the sacs is burst- this has allowed the spilled ova to begin to absorb water from the ground.

I found egg sacs that day, but also pieces of frog that hadnt been eaten(some almost intact animals) and a female frog torso that had been left holding the egg sacs. Not far from the frog remains were several otter spraint made of frog bones. There may well be a connection but herons, hooded crows, ravens, foxes and possibly buzzards all dine there at spawning season also so I can't attribute the frog remains to otters with certainty.

New post here with telling images-


nightfly's picture

Hi Soni

In this case I dont think the egg sack membrane is present. In my linked one below it is present. The egg mass seems to be sufficiently bound together to be able to sit like above after having slipped from the egg sack membrane. If the conditions are dry and it doesn't rain, the egg mass air dries. Just like above.