# Which animal is the best at processing its food? **URL:** \ **Category:** Factual Questions\ **Created:** [January 12, 2003, 1:42am UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059 "2003-01-12T01:42:27Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2003, 11:22am UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/21 "2003-01-13T11:22:32Z")
Sure, although of course they do have a _metabolism_, but you’re probably right - it’s a bit of a sidetrack from the letter of the OP. ---
**Author:** ![\_xiao\_wenti](https://avatars.discourse-cdn.com/v4/letter/_/b782af/32.png) [@\_xiao\_wenti](https://boards.straightdope.com/u/_xiao_wenti)\ **Post date:** [January 13, 2003, 11:32am UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/22 "2003-01-13T11:32:40Z")
IFRC small animals such as rabbits and guinea pigs (both quite tasty) are very efficient at conversion of input calories (1 input calorie ~ 0.3 output calories (of which some 50 percent can be consumed by you/me). Cattle are not very efficient at all ~ 5 %. Pigs are somewhere in the middle. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [January 13, 2003, 12:13pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/23 "2003-01-13T12:13:04Z")
Given the right feed pigs hit 30% feed conversion efficiency, in other words for every two pound they are fed they will put on 1 pound of weight. Kangaroos are even beter because the have such small brains. However things like tortoises will beat any mammal simply because they don’t have to waste energy as heat. ---
**Author:** ![smiling\_bandit](https://avatars.discourse-cdn.com/v4/letter/s/e9a140/32.png) [@smiling\_bandit](https://boards.straightdope.com/u/smiling_bandit)\ **Post date:** [January 13, 2003, 12:19pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/24 "2003-01-13T12:19:15Z")
> [@](#): > > I think it is named after the mythical multi-headed creature. Thats what the man said. Hydras effectively just sprout, like a hydra’s head. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 13, 2003, 1:29pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/25 "2003-01-13T13:29:08Z")
That and the fact that they are topped with a bunch of tentacles… ---
**Author:** ![Pablito](https://avatars.discourse-cdn.com/v4/letter/p/ed655f/32.png) [@Pablito](https://boards.straightdope.com/u/Pablito)\ **Post date:** [January 13, 2003, 5:43pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/26 "2003-01-13T17:43:41Z")
> [@](#): > > \*Originally posted by Blake \* > \*\*In believe the question is going to be impossible to answer. Efficiency is normally defined as 1/net input - net output. As such it’s going to depend on diet as much as the animal. AFAIK all animals are 100% efficient at digesting pure glucose. If you feed a hydra 100% glucose solution it will digest it at 100% efficiency. If you feed a the toed sloth 100% glucose solution it will digest it at 100% efficiency. Ditto for people, snakes and hairy nosed wombats. That’s the technical answer to the OP as stated: all animals are 100 efficient. > > People seem to be answering the question as it relates to the animal’s ‘normal’ diet by talking about snakes, hummingbirds and so on. The question then becomes ‘what animals has the most efficient digestive system at processing its normal food?’. That question is going to be very hard to answer because ‘normal’ varies so much. Animals that live on easily digestible substances like sugars or highly digestible proteins would rate very highly, so the hummingbirds, moths etc would al be in the running, along with chupacabras. Snakes, because they leave so much food behind as hair and bone wouldn’t be as efficient as mammalian carnivores that are a bit more selective about avoiding indigestible bits. > > Digestive efficiency doesn’t however normally depend on efficiency at digesting food, since that is so close to meaningless. Instead it normally translates to the proportion of material converted to body weight. Generally speaking the ‘cold blooded’ animals are the best at this, since so little energy is wasted maintaining unnecessary body temperature. \*\* This is an interesting point. A couple of questions might come out as a result of this: We might be tempted to ask ourselves, “But what if we revised the question to consider what animal does the most ‘work’ with that 100% digested glucose calorie?” That is, who uses the highest portion of that energy for pushing a lever or locomotion or whatever, rather than simply ‘maintaining body temp and metaboic processes’? If we could answer that, we might get closer to answering the OP. Of course, it’s still looks unanswerable (to me, anyway) because the percent of the calorie that goes toward work is going to vary greatly, depending upon the environmental conditions in which the animal finds itself: if we’re hanging around unclothed in the arctic, we’ll be using higher percentage of the glucose energy to keep warm than if we’ll walking around San Diego. Maybe we could postulate the ‘ideal’ external conditions, whatever those may be (yet another unanswerable), and then apply an ‘amount of work’ per calorie formula to determine efficiecy, but we’re quickly getting toward so many complicating issues that I can’t really see it getting resolved satisfactorily. So, there’s two cents off the top of my head. Someone please jump right in and elaborate or correct, as needed. Pablito ---
**Author:** ![Cisco](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@Cisco](https://boards.straightdope.com/u/Cisco)\ **Post date:** [January 15, 2003, 10:27am UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/27 "2003-01-15T10:27:16Z")
So, to put it bluntly, owls don’t crap? ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [January 15, 2003, 2:19pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/28 "2003-01-15T14:19:16Z")
\: " Okay, I’m convinced. What’s the best way to cook a mouse? " There’s a good recipe in “Never Cry Wolf” by Farley Mowat. Never tried it myself, though… Let us know how it comes out. ---
**Author:** ![Kalhoun](https://avatars.discourse-cdn.com/v4/letter/k/3bc359/32.png) [@Kalhoun](https://boards.straightdope.com/u/Kalhoun)\ **Post date:** [January 15, 2003, 2:28pm UTC](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059/29 "2003-01-15T14:28:39Z")
Which animal is the best at processing its food? Easy! The one with the best food processor! [Previous page](https://boards.straightdope.com/t/which-animal-is-the-best-at-processing-its-food/148059.md?page=1)