# Were there ever any 6-limbed animals other than insects? **URL:** \ **Category:** Factual Questions\ **Created:** [May 11, 2016, 2:53am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521 "2016-05-11T02:53:46Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 13, 2016, 4:40pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/61 "2016-05-13T16:40:23Z")
> [@Ignotus](#): > > Again: what joints has an octopus? Since octopodes are invertebrates, they have no joints. How about: To qualify as a limb, in vertebrates, there must be at least one joint. ---
**Author:** ![Bumbershoot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bumbershoot/32/3428_2.png) [@Bumbershoot](https://boards.straightdope.com/u/Bumbershoot)\ **Post date:** [May 13, 2016, 4:54pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/62 "2016-05-13T16:54:33Z")
According to Colibri, in post #24: > [@Colibri](#): > > I think that goes beyond the definition of limb, which is normally considered a jointed _or prehensile_ organ used for locomotion or manipulation. Italics mine ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 13, 2016, 5:18pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/63 "2016-05-13T17:18:56Z")
> [@Bumbershoot](#): > > According to Colibri, in post #24: > > Italics mine That will walk. (Get it? Limb, walk?) ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [May 13, 2016, 6:44pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/64 "2016-05-13T18:44:29Z")
so, to follow up: it’s because our ancestors were four-finned fish, with two pairs. are four-fins a better arrangement for swimming/fluid dynamics than six fins might be? ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 13, 2016, 6:58pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/65 "2016-05-13T18:58:09Z")
> [@Northern\_Piper](#): > > so, to follow up: it’s because our ancestors were four-finned fish, with two pairs. > > are four-fins a better arrangement for swimming/fluid dynamics than six fins might be? The earliest jawed fish apparently only had one set of paired fins, equivalent to the pectoral fins. I’m not sure when pelvic fins appeared. I don’t see any reason why a six-finned fish couldn’t have evolved. Some crustaceans have many pairs of swimming legs. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 13, 2016, 7:37pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/66 "2016-05-13T19:37:50Z")
In insects, the wings are homologous to the legs, but then, so are the antennae, some of the mouthparts, and several other structures. The first arthropods looked rather like centipedes, with some number of repeated nearly-identical body segments, each of which had two appendages. Along the line that led to the insects, those segments (and the appendages attached to them) specialized for various purposes, and many segments each fused into three main body divisions. But it’s fairly easy to revert those specializations, and so (for instance) to end up with a fruit fly with legs sprouting out of its head. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 13, 2016, 7:58pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/67 "2016-05-13T19:58:06Z")
> [@Northern\_Piper](#): > > are four-fins a better arrangement for swimming/fluid dynamics than six fins might be? In the aquarium fish I am familiar with, the other paired fins, the ventral, don’t seem terribly useful. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 13, 2016, 8:18pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/68 "2016-05-13T20:18:06Z")
> [@carnivorousplant](#): > > In the aquarium fish I am familiar with, the other paired fins, the ventral, don’t seem terribly useful. Most fish mainly use the tail fin for propulsion, and the paired fins mostly only for steering and control. There are exceptions. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 14, 2016, 1:28am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/69 "2016-05-14T01:28:21Z")
> [@Colibri](#): > > Most fish mainly use the tail fin for propulsion, and the paired fins mostly only for steering and control. There are exceptions. Yep. The [ventrals](http://aquariumfish.net/images_01/betta_male_blue_120125a2_w0640.jpg) on a beta appear to be merely decorative. On a [killifish](http://www.tfhmagazine.com/assets/013/54227_250wh.jpg), they are insignificant save for appearance. And he is damned pretty. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [May 14, 2016, 3:53am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/70 "2016-05-14T03:53:20Z")
Vertebrate anatomy would have to be strikingly different to facilitate additional pairs of limbs. The skeleton would add more weight for little gain, and the limbs themselves would add weight and consume energy for minimal or no payback. Insect legs contribute a lot less to their body mass, and the circulatory system that supports them is somewhat less complex than that of most vertebrates. So, really, one reason for the four limb arrangement of vertebrates is that it is practical. I mean, look at centaurs: darn ungainly critters. What the hell do you do with that extra stomach, anyway? ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 14, 2016, 1:27pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/71 "2016-05-14T13:27:17Z")
> [@eschereal](#): > > Vertebrate anatomy would have to be strikingly different to facilitate additional pairs of limbs. The skeleton would add more weight for little gain, and the limbs themselves would add weight and consume energy for minimal or no payback. Oh yeah? What about [Tars Tarkas?](http://img01.deviantart.net/28fe/i/2015/124/c/9/tars_tarkas_by_brentb9702-d1vi1kw.jpg) ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [May 15, 2016, 1:23am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/72 "2016-05-15T01:23:14Z")
I still think the DC comics in the mid-70s had the best imagining for Tars Tarkas. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 15, 2016, 10:34am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/73 "2016-05-15T10:34:02Z")
> [@Ignotus](#): > > Isn’t this a pretty lame distinction, though? They can certainly fold and unfold them at will. Did you miss the bit where they have to use their cerci to do it? ---
**Author:** ![dba\_Fred](https://avatars.discourse-cdn.com/v4/letter/d/c37758/32.png) [@dba\_Fred](https://boards.straightdope.com/u/dba_Fred)\ **Post date:** [May 15, 2016, 10:36am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/74 "2016-05-15T10:36:01Z")
> [@Blue\_Blistering\_Barnacle](#): > > So, if you crossed an elephant and a monkey, you could get a six-limbed mammal? 🙂 Then Groucho would have had to say: “One morning I shot an elekey/monkphant (?) in my pajamas. How he got his 6 limbs in my pajamas I’ll never know.” ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [May 15, 2016, 10:40am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/75 "2016-05-15T10:40:49Z")
> [@Northern\_Piper](#): > > I still think the DC comics in the mid-70s had the best imagining for Tars Tarkas. You mean [like thi](http://static4.comicvine.com/uploads/scale_large/0/4/11284-2561-12506-1-weird-worlds.jpg)s? Naah. ---
**Author:** ![Blue\_Blistering\_Barnacle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_blistering_barnacle/32/3386_2.png) [@Blue\_Blistering\_Barnacle](https://boards.straightdope.com/u/Blue_Blistering_Barnacle)\ **Post date:** [May 15, 2016, 4:22pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/76 "2016-05-15T16:22:20Z")
> [@Northern\_Piper](#): > > I still think the DC comics in the mid-70s had the best imagining for Tars Tarkas. Here’s the one I like best. Prob 'cuz it was on the cover of the first Barsoom book I read > **[Tars Tarkas](https://barsoom.fandom.com/wiki/Tars_Tarkas)** > > Tars Tarkas is the Jeddak of Thark, and a longtime ally of Warlord John Carter. Like all Tharks, he is a brute and can be cruel, but he has aspirations of raising the Tharks to become more than just an angry, subsistant coalition of tribes. He was... ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 15, 2016, 5:11pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/77 "2016-05-15T17:11:43Z")
I don’t recall how Burroughs described him, but I recall drawings where they were more heavily muscled. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [May 15, 2016, 9:19pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/78 "2016-05-15T21:19:05Z")
> [@carnivorousplant](#): > > Oh yeah? > What about [Tars Tarkas?](http://img01.deviantart.net/28fe/i/2015/124/c/9/tars_tarkas_by_brentb9702-d1vi1kw.jpg) Might as well include Zaphod in the mix, then. Unless you prefer not to have your head smacked with a slice of lemon wrapped around a large gold brick. ---
**Author:** ![Blue\_Blistering\_Barnacle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blue_blistering_barnacle/32/3386_2.png) [@Blue\_Blistering\_Barnacle](https://boards.straightdope.com/u/Blue_Blistering_Barnacle)\ **Post date:** [May 16, 2016, 4:44pm UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/79 "2016-05-16T16:44:30Z")
> [@eschereal](#): > > Might as well include Zaphod in the mix, then. Unless you prefer not to have your head smacked with a slice of lemon wrapped around a large gold brick. I suppose one might wonder what would happen if you crossed Zaphod Beeblebrox with a monkaphant, but knowing his proclivities, it’s probably already happened. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [May 19, 2016, 1:45am UTC](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521/80 "2016-05-19T01:45:28Z")
> [@Blue\_Blistering\_Barnacle](#): > > I suppose one might wonder what would happen if you crossed Zaphod Beeblebrox with a monkaphant, but knowing his proclivities, it’s probably already happened. This is becoming boring, but (Zaphod Beeblebrox)\*(monkaphant)\*sine(theta). [Previous page](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521.md?page=3) [Next page](https://boards.straightdope.com/t/were-there-ever-any-6-limbed-animals-other-than-insects/754521.md?page=5)