Dr Anjani Ganase, coral reef ecologist, brings the latest scientific research on an extinct giant shark, how tonka bean trees make space in the Panamanian forests and how our ears are like fish gills.

Lightning strikes a tonka bean tree

Researchers have discovered that mature tonka bean trees in the forests of Panama benefit from being struck by lightning. Typically, lightning strikes in the region can result in the death of 40-50 per cent of tall canopy trees in the Panamanian forests of Barro Colorado Nature Monument Forest.

Tonka bean trees and their large crowns are 50-70 per cent more likely to be struck by lightning than other species of tall trees. It seems that most tonka bean trees have a high likelihood of surviving a lightning strike and being relatively unscathed compared to other species. Not only is the tree undamaged but the parasitic vines and neighbouring trees are often worse off experiencing most of the burns.

[caption id="attachment_1153838" align="alignnone" width="1024"] Tonka bean tree almost two years after being struck by lightning with neighbouring trees dead (red arrow). Screenshot of video courtesy Gora et al. 2025. -[/caption]

Using over 40 years of collected data, scientists confirm that a lightning strike of a tonka bean tree results in about 2.4 tons of biomass loss in surrounding trees, while attached vines suffer up to 80 per cent die back. It is thought that the trunk of the tonka bean tree is more conductive, allowing the electricity to flow through the tree rather than building up heat and causing burning. Loss of surrounding trees and vines extends the life span of the tonka bean tree (14 fold), thereby providing more opportunities for reproduction.

The average mature tonka bean tree in the Panamanian forest can grow to 40 m in height with a trunk diameter bigger than 60 cms. These trees live to several hundred years, and it is estimated that over the lifespan of a mature tonka bean tree, it can be struck by lightning five times on average. This means that there is recurring control of competitive plants and parasitic vines.

Our evolutionary origins are fishy

The outer ear of a mammal is oddly shaped and weird-looking. The ear folds seem unnecessary in contrast to the smooth conical disc devices, like the satellite dish, that we’ve invented to collect sound signals. The path of evolution is meandering and mysterious. All land animals evolved from the ocean, a place that really has no use for an ear. However, on land, the growth of ears provided clear benefits for mammals.

Researchers from the School of Medicine, University of Southern California, found that the outer ear of mammals can be linked evolutionarily to the gills of ancient fish. Both organs share a unique tissue called elastic collagen that make the outer ear (and gills) flexible but durable. In present day, the tissue is predominantly found in mammals and it seems the outer ear is likely to have evolved from ancient fish gills.

As elastic collagen is not fossilised, scientists had to use DNA wh