33

There are (at least) three important factors to consider here; evolution under selection requires genetic variation upon which to act, selection can act on covarying traits causing trade-offs, and adaptation also occurs in the predator. A lot of this is covered elsewhere on this site (including the effects of the other mechanisms of evolution), but little ...


31

No, I don't think auto-regulation explain much in the population sizes of predators. Group selection may explain such auto-regulation but I don't think it is of any considerable importance for this discussion. The short answer is, as @shigeta said [predators] tend to starve to death as they are too many! To have a better understanding of what @shigeta ...


31

Thanks to the other answer for pointing me in the right direction with some references. It seems that two biologists in the early 1990s had a back-and-forth over this topic in The Quarterly Review of Biology.1,2 A statement of the problem: The function of menstruation is a central enigma of mammalian, and especially primate, reproductive physiology. Each ...


17

There are two reasons for this: evolutionary trade-offs and coevolution (the "Red Queen hypothesis", as mentioned in the comment above by Luigi). Evolutionary trade-off describes situations where one trait cannot increase without a decrease in one or more others. Some hypothetical examples: longer legs may help run faster, but past a certain point, it will ...


14

Remi.b's answer is an excellent one, and this should be taken as a supplement to it: It's possible your simulation is correct The Lotka-Volterra equations are what is known as a deterministic model, and it describes the behavior of predator-prey systems (in a somewhat simplified fashion) in large populations. Small populations are subject to what is known ...


10

They're not fast enough A hornet has a top speed of around 40 kph, while a rabbit is only a touch faster, a deer can hit 75 kph (all figures from Wikipedia). In order to act as hunting insects they need to match the speed of these large animals in large enough numbers to surround and overpower them but these animals could easily match their speed or outpace ...


10

There are both costs and benefits to being able to run faster, both as a predator and as a prey animal. In short, maintaining the large muscles necessary to outrun a cheetah every time is metabolically expensive. So it isn't a matter of being able to always outrun a predator--it's a matter of how to optimally allocate precious resources either to ...


10

It is a very nice question. From wikipedia: Though there is some disagreement in definitions between sources, menstruation is generally considered to be limited to primates. Overt menstruation (where there is bleeding from the uterus through the vagina) is found primarily in humans and close evolutionary relatives such as chimpanzees. It is common in ...


9

The behaviour that you describe is common in most animal species, as part of the natural trade-off between access to food, minimizing risk, habituation and hunger. Animals usually choose to forage in high-quality habitats that has a low risk of predation, but if food sources are depleted (or competition and/or territoriality is high) they will move to other ...


9

One of the possible adjustments of these mathematical models is to introduce a "place to hide", making some (small) percent of the prey population not accessible (or much more difficult to access) for predators. After the number of predators decreases from starvation, prey individuals are relatively safer outside the "place to hide" and can grow over this ...


8

They do exist. Many such examples can be found. Such as the most terrifying one, being social groups formed by Spiders, Anelosimus eximius documented here. Colonies of upto 9000 individuals have been documented by the scientists in their report. Also let's not forget Piranhas, another group of social animals, which take down much larger prey due to their ...


8

Caiman and Anacondas - though each hunts the other at a stage of development when the hunter is larger.1 2 Occasionally this occurs with Orcas and Sharks.3 Some species of shark3 Spiders and mantids4 Alligators and catfish (catfish prey on infant alligators) Many species of predatory fish Some species of constrictor and venomous snake. Some frogs and Epomis ...


6

Good question. There is no fundamental difference between parasites and predators. Ecological Interaction In terms of ecological interaction, they are both defined as an interaction where one species benefits and the other suffers from the interaction. Intuition parasite vs predator In general predation is viewed as a big individual eating a smaller ...


6

Parasitism – a parasite that lives on or in an host, obtaining food from the host and harming it. Example: Ixodes ticks use white tailed deer as a host Parasite is smaller and weaker than the host Parasite may feed over the host from outside or inside In parasite-host relationship a weaker organism is benefitted Host specificity is more common The host ...


6

Try out using Google Scholar to take a more scientific literature-based approach to your search. Frick et al. (2009)1 found that about 42% of logerhead sea turtle (Caretta caretta) stomachs contained remnants of G. atlanticus. We were able to identify G. atlanticus in the diet of loggerheads because whole or nearly intact specimens were present. ...


5

You need to add Bell curves to your simulation. The most important curve to simulate is the nutritional quality of the prey though there are plenty more thing to curve like speed and virility for prey and predators both. Nature uses lots of Bell curves so they must be good for something, such as softening the harsh effects of pure exponential growth. I ...


5

Larger predators need a large range on which to find potential prey. An island might be bigger than the normal range of a predator, but too small to support a large enough breeding population (because of inbreeding, and because a brief lack of food, disease, or other insult could wipe out the entire population, rather than just a few individuals).


5

There is a lot to say on this question. I will try to keep it short, to the risk of oversimplifying the problem. I can think of three main reasons: 1. Predation does not necessarily means death of the prey Most of predation does not directly kill the prey. Typically herbivory, will often damage the prey but a single individual won't kill the prey entirely. ...


4

New Answer, based on first comment by user2686410 and subsequent edits to the question. I have interpreted "synchronizing their own generations to divisors..." to mean synchronizing the length of the life cycle. I am happy to hear of another interpretation. First, the overall goal of Goles et al. (2001) does not seem to test hypotheses related to the ...


4

This question can be tackled in several ways, and also seems to contain a couple of misconceptions about ecological processes (e.g. problematic group-selection ideas and how species 'fit' into the ecosystem). However, I think it is most usefully answered from the perspective of life history theory and the evolution of life histories (see e.g. Roff, 2002 and ...


4

I don't have an answer to this but there are a number of elements I think can be helpful for you in finding an answer. First, a helpful word for searching here if you didn't know or hadn't thought of it is "trophic", as in "trophic level", as in "how high this organism is in the food chain". Making searches related to fish and trophic levels I didn't find ...


4

You are indeed correct that the prey of predators are usually more common than their predators, especially if you focus on "true" predation (i.e. remove parasitism and parasitoidism). As a rule of thumb, the energy conversion between trophic stages is 10% (first proposed in Lindeman, 1942), which sets one sort of bound on the density relationship between ...


4

A python will eat an alligator: Source: http://www.miamibeach411.com/news/python-snakes and an alligator will eat a python: Source: https://www.palmbeachpost.com/news/gator-chows-down-python-florida-golf-course/9HUGKYz7j3qF1BGJwc2RUL/


3

Short answer I think the author is mostly right, but there are exceptions. Background The author is probably referring to hunting as being an "active foraging" strategy, while he ascribes the foraging behavior of reptiles to be a "sit-and-wait" strategy. Active hunters include the classic, and dramatic high-speed, long-distance pursuit strategies deployed ...


3

The way you pose the question, as in what mechanisms limit the fertility of predators, together with your comment about the distinction to the population dynamic aspect, strongly that what you are thinking about an adaptional mechanism here and asking about its characteristics, right? In that case, this is very similar to the kind of scenarios you find in ...


3

In a given area there can be only a limited number of top predators due to resource limitations. Furthermore, as top predators are not hunted upon, a relatively high percentage of offspring will survive until adulthood. Hence, producing many offspring doesn't make sense as survival rates are high, while resources are limited. Producing many offspring is a ...


3

The data used in the graph you posted seems to be from Bambach. 2002. Supporting predators: changes in the global ecosystem inferred from changes in predator diversity (in Kowalewski & Kelley. The Fossil Record of Predation) - see fig 19b - and, if so, is specifically dealing with marine predators. I don't have time to look at that paper closely (it is ...


3

Unfortunately for you, such animals do exist (O'Donnell et al. 2005). This is a direct field observation of a swarm of army ants attacking and consuming a 60cm long earthworm, as well as consuming a 10cm long snake. From the linked article: We collected workers from two Cheliomyrmex andicola foraging raids. During raid 1 on 26 September 2003 at 1030 ...


3

You can smell roughly where your pan is cooking, but you can hear it with more precision, in order to pin point something you would tend to use your ears, especially if it is under snow. Cats use all their senses and experience to hunt. The mice have tunnels under the snow to get around and they mark their territory randomly, so the smell doesn't provide a ...


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