Palaeo After Dark

The gang have a “Shark Week” and discuss two papers about the ecology of modern tiger sharks. The first paper talks about a unique feeding strategy for some tiger sharks in which they can consume a fairly large amount of song birds. The second paper discusses how tiger shark populations are distributed around the islands of Hawaii, a place known for fairly high concentrations of tiger sharks. Meanwhile, James informs us of an important holiday, Curt imagines the ultimate battle of goose and shark, and Amanda decides to take charge of the podcast.


Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at how these big animals with teeth that move through the water live. The first paper looks at what these big animals in the water are eating. People have been catching these big animals in the water and seeing what is inside of them. During some times in the year, usually the fall, these big animals in the water somehow eat a whole hell of a lot of these very small animals that talk a lot and move through the air. Turns out that most of the big animals in the water eating these small animals from the air that talk a lot are young but not babies. This shows a very interesting case where food comes from the land into the water. Often, food moves from the water into the land but this is the other way around.

The other paper looks at where these big animals live, focusing on a place where a lot of these big animals have had attacks with people. This paper showed that this one place seems to get a lot of these big animals because they like to make babies there. There is a lot of stuff this paper goes through, but the big important point is that this is a place where people play and move in water, and it is also important for these big animals, so this means that people and these big animals are going to come together at some point and the people should be told about this. Another cool thing is that the number of big animals in the area and the number of attacks are not the same, meaning that more of these big animals does not mean more attacks. It shows that making sure people know about these big animals is probably more important, and that scared attempts to kill these big animals do not make the problem better, and ends up very bad for the world.



Meyer, Carl G., et al. "Habitat geography around Hawaii’s oceanic islands influences tiger shark (Galeocerdo cuvier) spatial behaviour and shark bite risk at ocean recreation sites." Scientific reports 8.1 (2018): 4945. 

 Drymon, J. M., et al. "Tiger sharks eat songbirds: scavenging a windfall of nutrients from the sky." Ecology

Direct download: Podcast_165_-_Sharks_for_St_Crispins_Day.mp3
Category:general -- posted at: 3:00am EDT

The gang talks about two papers that are interested in iterative evolution, the repeated evolution of the same or similar morphological characteristics within or among species. Specifically, they are focused on iterative evolution in species on islands. The first paper they discuss looks at how being flightless might have evolved multiple times on the same island within the same species of rails. The second paper looks at repeated changes in developmental timing associated with climatic changes on an island. Also, James is an expert, Curt comes up with the best new Blue Sky series for the USA network “Rails and Snails”, and Amanda changes the podcast’s format.


Up-Goer Five (Curt Edition):

Our friends talks about two times that weird things happen when animals get on an piece of land that is surrounded on all sides by water. The first paper looks at small light flying things. When these flying things get onto a piece of land surrounded by water, they seem to stop flying. However, they find these remains of these light flying things on this one piece of land so they can see how the way these remains look change, because the way these remains look will tell us if these light flying things had decided to stop flying. The cool thing is that many different flying groups of this same flying thing landed on this pieces of land surrounded by water and all decided to stop flying on their own. So the story for these light flying things is that they land on this piece of land surrounded by water, they stop flying, and then they die from breathing water when the land goes under, and then when the land is above the water, they repeat.

The second paper looks at how these things that sit there, have a rock around them, and pull food out of water change over time. What the paper finds is that these little things with a rock around them look very different when the water goes up and down. The paper says that this is because of changes in how these little animals with a rock around them grow up. Do they take longer to grow up, do they look more like grown ups or do they look more like babies? The changes they see in how these things grow up happen at the same time as changes in where the water is, as well as how hot or cold it is.



Hume, Julian P., and David Martill. "Repeated evolution of flightlessness in Dryolimnas rails (Aves: Rallidae) after extinction and recolonization on Aldabra." Zoological Journal of the Linnean Society (2019). 

 Hearty, Paul J., and Storrs L. Olson. "Environmental Stress and Iterative Paedomorphism in Shells of Poecilozonites (Gastropoda: Gastrodontidae) from Bermuda." Palaios 34.1 (2019): 32-42. 

Direct download: Podcast_164_-_Rails_and_Snails.mp3
Category:general -- posted at: 3:00am EDT