# Which animal grows the most from live birth to maturity? **URL:** \ **Category:** Factual Questions\ **Created:** [April 26, 2013, 4:16pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769 "2013-04-26T16:16:12Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![drew870mitchell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drew870mitchell/32/3946_2.png) [@drew870mitchell](https://boards.straightdope.com/u/drew870mitchell)\ **Post date:** [April 26, 2013, 4:16pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/1 "2013-04-26T16:16:12Z")
For reference, humans start at 6-9 pounds, and end up anywhere from 100-300 (ordinarily). So far I have bears: born at under a pound, grow up to 500 pounds. [http://www.4information.com/trivia/large-bear-birth/](http://www.4information.com/trivia/large-bear-birth/) ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [April 26, 2013, 4:21pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/2 "2013-04-26T16:21:23Z")
A kangaroo might qualify but he is really a fetus at birth. Marsupials in general are very small at birth. ---
**Author:** ![Ambrosio\_Spinola](https://avatars.discourse-cdn.com/v4/letter/a/9de0a6/32.png) [@Ambrosio\_Spinola](https://boards.straightdope.com/u/Ambrosio_Spinola)\ **Post date:** [April 26, 2013, 4:31pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/3 "2013-04-26T16:31:30Z")
For a purely literal answer, you would be looking at a blue whale calf, since it grows into the biggest animal that is ever known to have existed on Earth. But an adult isn’t 500 times bigger than a calf, if that’s what you’re asking. ---
**Author:** ![drewtwo99](https://avatars.discourse-cdn.com/v4/letter/d/d07c76/32.png) [@drewtwo99](https://boards.straightdope.com/u/drewtwo99)\ **Post date:** [April 26, 2013, 4:31pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/4 "2013-04-26T16:31:44Z")
Blue whale is 170 tons on average as an adult, a calf is born at around 2.5 tons, according to wikipedia. So percentage-wise that’s not that impressive, but in just sheer numbers of pounds added from infancy to adulthood, I don’t think you’re going to beat that. ETA: Ninja’d!! ---
**Author:** ![Enilno](https://avatars.discourse-cdn.com/v4/letter/e/58f4c7/32.png) [@Enilno](https://boards.straightdope.com/u/Enilno)\ **Post date:** [April 26, 2013, 4:53pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/5 "2013-04-26T16:53:07Z")
I don’t have any numbers, but since the OP only specifies live birth, we may want to consider some of the non mammal viviparous animals, like seahorse. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [April 26, 2013, 5:15pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/6 "2013-04-26T17:15:24Z")
By “grows the most” do you mean adds the most weight or increases by the biggest percentage? ---
**Author:** ![Dinsdale](https://avatars.discourse-cdn.com/v4/letter/d/97f17d/32.png) [@Dinsdale](https://boards.straightdope.com/u/Dinsdale)\ **Post date:** [April 26, 2013, 5:18pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/7 "2013-04-26T17:18:11Z")
Not on point on either the live birth or greatest increase, but just last night I was reading about how much weight cardinals pack on in the first week or so after they hatch. I think they increase their weight by something like 6x in their first 7-9 days or so. Struck me as a pretty incredible growth rate. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [April 26, 2013, 5:52pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/8 "2013-04-26T17:52:05Z")
I’m having a hard time finding out how much newly hatched lobsters weigh. I saw on on site what they look like when they are 8mm long, but I know they start out smaller. Some get to weigh as much as 40 pounds. ETA: But that’s not a live birth. ---
**Author:** ![Turpentine](https://avatars.discourse-cdn.com/v4/letter/t/ecd19e/32.png) [@Turpentine](https://boards.straightdope.com/u/Turpentine)\ **Post date:** [April 26, 2013, 5:56pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/9 "2013-04-26T17:56:05Z")
I’m voting for the red kangaroo if you’re going by percentage. The neonate is about 2 grams, a full-sized male is 85kg. So it increases its mass from birth to maturity by 42,000 times. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [April 26, 2013, 5:58pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/10 "2013-04-26T17:58:32Z")
I’m thinking frogs. Those tadpoles are damn small. ---
**Author:** ![Si\_Amigo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/si_amigo/32/2877_2.png) [@Si\_Amigo](https://boards.straightdope.com/u/Si_Amigo)\ **Post date:** [April 26, 2013, 6:00pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/11 "2013-04-26T18:00:03Z")
> [@Turpentine](#): > > I’m voting for the red kangaroo if you’re going by percentage. The neonate is about 2 grams, a full-sized male is 85kg. So it increases its mass from birth to maturity by 42,000 times. But Kangaroos are still pretty much attached to and protected by their mothers. I’m thinking boots on the ground (or at least butt) needs to be criteria here. ---
**Author:** ![Michael63129](https://avatars.discourse-cdn.com/v4/letter/m/3da27b/32.png) [@Michael63129](https://boards.straightdope.com/u/Michael63129)\ **Post date:** [April 26, 2013, 8:18pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/12 "2013-04-26T20:18:17Z")
> [@Ambrosio\_Spinola](#): > > For a purely literal answer, you would be looking at a blue whale calf, since it grows into the biggest animal that is ever known to have existed on Earth. But an adult isn’t 500 times bigger than a calf, if that’s what you’re asking. If you start from conception, nothing else comes close to a blue whale, which increases in weight quadrillions of times (humans (~0.07 metric tons) have around 10 trillion so if a blue whale’s (170 metric tons) cells average the same size, then it has around 25 quadrillion cells, which all come from one cell). ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [April 26, 2013, 8:24pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/13 "2013-04-26T20:24:40Z")
> [@tdn](#): > > I’m having a hard time finding out how much newly hatched lobsters weigh. I saw on on site what they look like when they are 8mm long, but I know they start out smaller. Some get to weigh as much as 40 pounds. > > ETA: But that’s not a live birth. I was gonna nominate octopuses for the same reason…and must disqualify them also. Baby octopuses are incredibly tiny; the ones I saw were maybe two mm across. I was also thinking of the kangaroo, but if that’s disqualified, I think the whales take the krill. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [April 26, 2013, 8:52pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/14 "2013-04-26T20:52:29Z")
Hmm. I wonder how much a larval giant clam weighs… ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 26, 2013, 10:23pm UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/15 "2013-04-26T22:23:22Z")
> [@Smeghead](#): > > Hmm. I wonder how much a larval giant clam weighs… Blake provided the answer to that in this thread: [Largest size difference between progeny and adult](http://boards.straightdope.com/sdmb/showpost.php?p=12953336&postcount=5) ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [April 27, 2013, 5:14am UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/16 "2013-04-27T05:14:25Z")
> [@Si\_Amigo](#): > > But Kangaroos are still pretty much attached to and protected by their mothers. I’m thinking boots on the ground (or at least butt) needs to be criteria here. In which case we also have to rule out humans and bears, whose young are also still pretty much attached to and protected by their mothers. Since the OP specifically included both humans and bears on the list, I’m thinking that no such criterion exits. But the winner isn’t going to any vertebrate anyway. Most sponges produce live young, and the larvae weigh less than 1/100th of a gram at the time of release despite being perfectly self sufficient. I’m not sure what a large sponge weighs. Certainly in excess of 100 kg. So that gives us a size increase between independent juvenile and mature adult of 10, 000, 000 fold. No way any vertebrate can come close to that. ---
**Author:** ![shijinn](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@shijinn](https://boards.straightdope.com/u/shijinn)\ **Post date:** [April 27, 2013, 5:22am UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/17 "2013-04-27T05:22:53Z")
could we also have an answer for the opposite? which animal grows the least? ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [April 27, 2013, 5:33am UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/18 "2013-04-27T05:33:23Z")
The typical definition of “birth” in the biological sense – “the emergence and separation of offspring from the body of the mother” – excludes most if not all invertebrates. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [April 27, 2013, 7:21am UTC](https://boards.straightdope.com/t/which-animal-grows-the-most-from-live-birth-to-maturity/656769/19 "2013-04-27T07:21:07Z")
> [@Gary\_T](#): > > The typical definition of “birth” in the biological sense – “the emergence and separation of offspring from the body of the mother” – excludes most if not all invertebrates. Ahh, no, it doesn’t. Can you explain how it excludes \*any \*viviparous invertebrate? For example, in what sense is the procreation method of blowflies or sponges not “the emergence and separation of offspring from the body of the mother”?