By Denis O’Connor

Wharfedale Naturalists Society

ON two nights at the end of November a member of Wharfedale Naturalists, Linda Lukats, discovered deposits of white, globular jelly, each with an attached mass of tiny black eggs, on the paving beside the small pond in her front garden on Bridge Avenue in Otley (photo, scale in cm).

She took some photos, did some research herself and forwarded the photos to another WNS member, Anne Riley, who looked into it further. They agreed that the deposits were “Star Jelly” from the innards of a frog.

Star Jelly was a new concept to me but is actually an ancient one, having been reported as far back as the 14th century and having inspired all sorts of strange ideas including that it fell to earth in meteor showers.

The more prosaic explanation is that a predator, having ripped apart the body of a female frog (Female frogs develop eggs in the late summer, retaining them ready for the following spring), discards the ovum jelly with eggs attached. The jelly expands enormously as it absorbs dew or rain. Alternatively, having eaten the frog, the ovum jelly expands in the guts of the predator and is vomited up.

The internet came up with a variety of photos of “Star or Astral Jelly” including slime moulds and fungi but several strikingly similar to those from Linda’s garden. One was from the Peak District in November 2020 and thought to have been vomited up by a fox, heron or otter.

In the BBC programme, “Nature’s Weirdest Events” from 2015, Chris Packham showed a specimen of star jelly and sent it for DNA analysis which confirmed it was from a frog.

The question remained as to the identity of the predator in this case so I set up a trail camera overnight overlooking the edge of the Bridge Avenue pond. Rather disappointingly, it recorded no otters or early morning herons from the nearby river but two cats approaching the pond with one of them sitting expectantly at the edge.

The most likely explanation seems to be that the predator was a cat which had surprised frogs on their way to hibernate in the pond or which had emerged from the pond on previous evenings that had been quite mild.

All certainly unusual but more convincing than the star jelly having fallen to earth from a meteor!