Tag Archives: predators

Street Urchins

Sometimes dinner turns into a mob and bites back.

Well at least that’s what it looks like…

In a shocking turn of events a common sun star (starfish species) was gobbled up by a group of sea urchins (their natural prey species) at a research station in Sweden. Which is just a little bit out of character for the vegetarian lawnmowers that are sea urchins – although make no mistake they can vacuum up a kelp forest if given half the chance.

Although the ‘why’ as to what drove the sea urchins to turn on the starfish (a case of hunger perhaps, or an attempt to remove the threat of predation) remains unclear, the interesting thing is that although the sea urchins have a comparatively simple nervous system (they don’t even have a true brain), they are still able to execute an organised form of attack. This attack strategy has been termed ‘urchin pinning’ by the research team and is usually instigated by one individual that starts the ‘attack’ and is then joined by the other sea urchins who begin munching away at the starfish. They start at the tips and moving inwards, leaving the starfish unable to get away…

The original research article can be found here: https://doi.org/10.1111/eth.13147

A note for sensitive readers: Although many starfish were harmed in the making of this comic they are expected to make a full recovery (physically at least).

An Attempt To Understand Painlessly Killing Predators

Image Credit: Larissa Uhryn, CC BY-SA 4.0, Image Cropped

I just want to start this article off by saying that I had TWO amazing pieces scheduled for today, and I’ve put them both off for next week (my apologies to Yi-Kai Tea and Charlie Woodrow). I’ve done so because the start of this week saw a paper come to Ecology Twitter’s attention that is just plain wild (excuse the pun).

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The Multiple Enemies of Prey Species

Image Credit: Mike Baird, CC BY 2.0, Image Cropped

The importance of functional responses among competing predators for avian nesting success (2019) Ellis et. al, Functional Ecology, https://doi.org/10.1111/1365-2435.13460

The Crux

In our ever-changing world, natural populations of different species are experiencing changes in both size and range. Part of the difficulty in predicting or responding to these changes is that ecological systems are made up of complex webs of species interactions, all of which have the potential to affect how populations respond to these changes. One of the most important interaction that occurs between species is predation.

Predators can affect the way prey species look, behave, and even where they live (see the Did You Know section). Different predator species can have varying effects on their prey, and as such it is important to consider these differences whenever wildlife managers make policy decisions on how to manage and control endangered populations. The authors of today’s paper were interested in uncovering how different predator species affected prey, using the snowy plover (Charadrius nivosus).

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Speed Kills. Or Does It?

In an eat or be eaten world, the survival of the fittest can come down to who the most physically able is. Today’s paper investigated the athletic ability of sidewinder rattlesnakes relative to their kangaroo rat prey. (Image Credit: TigerhawkvokCC BY-SA 3.0, Image Cropped).

Determinants of predation success: How to survive an attack from a rattlesnake (2019) Whitford et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13318

The Crux

In nature, many animals are part of the predator-prey cycle. One animal is subject to being eaten by the other, and must escape in order to avoid this fate. Despite what you may have seen on a variety of amazing nature documentaries, most predator-prey interactions don’t involve some flashy takedown and subsequent meal for the predator. Predators usually fail far more often than they succeed, with one of the most successful animals on the planet (the killer whale) only succeeding HALF of the time.

These interactions between predators and their prey depend on two things: the predator’s physical attack ability/performance and the prey’s escape ability. Basically, who is more athletic? There are many different ways that predators try and take down their prey, but the authors of today’s paper wanted to know what the key aspects of the predator-prey interaction are, and which of them is most important for each participant.
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Fading Into the Background

Mostly limited to ocean animals, transparency is thought to help escape predators by blending the animal in with its environment, but is this what actually happens? (Image Credit: birdphotos.com, CC BY 3.0, Image Cropped)

Transparency reduces predator detection in mimetic clearwing butterflies (2019) Arias et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13315

The Crux

Predators are one of the strongest forces of selection in the natural world, and as a result it can be quite costly to stand out and be more easily noticed. This means that in order to survive, animals must adapt to avoid predators. Besides running away from what is trying to eat you, your best bet is to evolve body coloration that helps you avoid being seen by a predator.

Animals that rely on blending in will match the color or even the texture of their backgrounds, but when prey species live in areas where they cannot easily blend in (like plankton in the water column) they often evolve to be transparent. Unlike their marine counterparts, transparency is normally rare in terrestrial animals. The clearwing butterfly is one notable exception to this rule, and the authors of today’s paper wanted to test whether or not these clear wings actually reduce predation.
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Bringing Back Carnivores

Image Credit: Per Harald Olsen, NTNU, CC BY 2.0, Image Cropped

In my previous posts on rewilding and wild boar, I talked about the effects of reintroducing species that were previously found in Norway. Now, I want to talk more about the large carnivores in Scandinavia which serve as protection against invasive species. This opinion piece is coming from an ecologist and a foreigner, so treat this like a Scandic breakfast buffet and take what you want.

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