I'm trying to identify which 2 species, one predator species and one prey species that have the biggest size difference. Specifically, which predator hunts the largest prey relative to itself?

I'm looking for the pair with the smallest predator taking the largest prey but relative to each other, not the other way around.

Some limiting factors to the question:

  1. Parasites don't count. Parasites will, ideally, repeatedly feed on the same host for as long as possible. Killing the host will, eventually, remove the resource, which is undesirable for the parasite (it can't keep feeding on the host if the host ceases to exist). I'm looking for a predator prey relationship that does not do this in any way, shape, or form. Even if the predator does not consume the majority of the prey, the portion consumed must be vital to the prey, or the prey must be killed in order to access it or overcome resistance to it.

  2. Animals eating plants don't count. Animals eating other animals only please.

  3. Pack hunters don't count. Lions, wolves, orcas, army ants, etc., don't count because packs can come in so many shapes and sizes that it makes it impossible to pin down a size ratio between the pack and the prey. Single predator individuals only, please.

  4. Scavenging doesn't count. Predators might also scavenge, but prey species used in the size comparison should only include species that the predator actively hunts as part of its regular active hunting routine (even if intermittently or seasonally).

  5. Intentional prey sharing doesn't count. Sure, a predator might have it's prey stolen after a kill, that's fine. In many predator species, parents will share kills with offspring until they are capable of hunting for themselves, that's fine too. But nothing like the Tarantula Hawk that doesn't actually eat the "prey" itself, but rather leaves it to be eaten by offspring later. But typical behavior, even in the presence of non-self-reliant offspring, and assuming another predator doesn't take the kill by force, should be for the individual predator that makes the kill to also be the individual that consumes the largest share of the nutritive portions of the prey.

  6. Body mass is the primary measurement for "size". Since length, width, height, etc., can vary widely based on body plan, let's use mass as the measurement for "size" for the purposes of this question.

  7. Size of the predator should be the mass of a 'typical' or 'average' adult member of the species that performs the actual hunt / kill. For species with significant sexual dimorphism in relation to size between male and female, use the size of whichever sex is generally larger.

  8. Size of the prey should be the mass of the 'average' specimen taken in a predation event. For example, Lions (yes, I know I excluded them in the 'pack' section earlier, but for the sake of example), lions will eat elephants. This is most commonly scavenging, rather than hunting. And when it is due to hunting, it's more often calves, not adult elephants, that are taken in the hunt. So (if lions were allowed, and were compared to elephants) the scavenged elephants wouldn't count toward the 'average', only the hunted ones, and the average would be closer to the size of a calf, rather than an adult, due to the higher frequency of predation events involving calves.

  9. The ratio matters, not the absolute mass difference. I'm looking for the pair with the biggest ratio, or percentage difference, not the greatest sheer difference in mass. For example, Pair A is a 20 pound predator taking a 30 pound prey, this is only a 3:2 ratio and a 10 pound difference. Pair B is a 1 pound predator that takes a 5 pound prey, which would have a much larger ratio of 5:1 despite only a 4 pound difference. Pair B is the winner here, by ratio.

Given all of this, which two species, that have a predator and prey relationship, have the greatest mass difference between the predator and the prey?

  • $\begingroup$ Have you googled this? Or "tiny animal predators"? Please give evidence of research have you done to answer this question yourself, which is a requirement on this site. Thanks. $\endgroup$ Commented Sep 27, 2023 at 16:27
  • $\begingroup$ @Darlingtonia I'm actually looking for the pair with the smallest predator taking the largest prey, not the other way around. I'll update the question to clarify. $\endgroup$
    – Harthag
    Commented Sep 27, 2023 at 16:31
  • $\begingroup$ @anongoodnurse Yes, I attempted many such searches, but the question is too complex for that type of search, as far as I've been able to determine. For example, your suggested search criteria, of "tiny animal predators" would be useless, as the absolute size of the predator isn't actually relevant. The ratio of the sizes is the relevant factor here, which is all but impossible to put in to an internet search, and yields useless or no results at all, when attempted $\endgroup$
    – Harthag
    Commented Sep 27, 2023 at 16:54
  • $\begingroup$ I recently found a beetle larvae specialized to kill an earth worm that was 50+ times more massive than it. your question doesn't make sense to me totally... A parasite is just a predator that eats the prey slowly, and some parasites do kill the prey. If a tiny spider kills a human and eats a piece, where does that fit into the relativity of the query? it doesn't make sense to kill a prey which can supply so much food that it goes mouldy when only 0.1% has been comsumed. $\endgroup$ Commented Sep 27, 2023 at 19:59
  • $\begingroup$ @bandybabboon Parasite, parasitoid, predation...Yes, the lines are blurred. There are no spiders that hunt humans intentionally as a food source, so that would be a defensive kill, followed by opportunistic scavenging, not predation. Parasitoids do kill the host, eventually, but keep it alive as long as possible, for other reasons realated to their life cycles, such as feeding young, defense, or environmental concerns, etc. For simplicity, I'm looking for only those that are clearly not parasites or parasitoids, but rather clear and unambiguous predation. $\endgroup$
    – Harthag
    Commented Sep 28, 2023 at 20:58

1 Answer 1


I think the Black Swallower (Chiasmodon niger) is a good contender. This fish can (at least according to Wikipedia and reference therein) can swallow other fish that are up to twice its length and 10x its mass.

For land based predators, the Least Weasel (Mustela nivalis) is capable of killing prey 5-10x its weight, though these instances are believed to be rare (at least rarely observed), though they will take birds like Chickens occasionally too. Diet is normally much smaller - rats, mice etc.

  • $\begingroup$ Why would someone downvote this? $\endgroup$ Commented Sep 28, 2023 at 9:59

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