# Basic zoology terminology about excretions

**URL:** <https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425>\
**Category:** Factual Questions\
**Created:** [March 3, 2011, 11:55pm UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425 "2011-03-03T23:55:48Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![janeslogin](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@janeslogin](https://boards.straightdope.com/u/janeslogin)\
**Post date:** [March 3, 2011, 11:55pm UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425/1 "2011-03-03T23:55:48Z")

</div>

I’ve a basic zoology query about terminology. What is it called when the creature such as fish and birds excrete the feces and urine from the same orifice?

---

<div class="post-metadata">

**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\
**Post date:** [March 3, 2011, 11:57pm UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425/2 "2011-03-03T23:57:54Z")

</div>

Well, the orifice is called the cloaca. Is that what you are asking?

---

<div class="post-metadata">

**Author:** ![janeslogin](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@janeslogin](https://boards.straightdope.com/u/janeslogin)\
**Post date:** [March 4, 2011, 12:26am UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425/3 "2011-03-04T00:26:52Z")

</div>

> [@njtt](#):
>
> Well, the orifice is called the cloaca. Is that what you are asking?

Close but not exactly however. Is there a categorical term for animals that have a cloaca? Is there a taxonomic category for fish, reptiles and birds?

---

<div class="post-metadata">

**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\
**Post date:** [March 4, 2011, 12:38am UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425/4 "2011-03-04T00:38:23Z")

</div>

I doubt it. Not a “real” taxonomic category, anyway. Anything that includes fish along with reptiles and birds is going to include mammals too. [See here (with added erroneous XKCD).](http://scienceblogs.com/pharyngula/2011/03/soon_to_appear_on_a_thousand_h.php)

---

<div class="post-metadata">

**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:** [March 4, 2011, 4:02am UTC](https://boards.straightdope.com/t/basic-zoology-terminology-about-excretions/573425/5 "2011-03-04T04:02:33Z")

</div>

> [@janeslogin](#):
>
> What is it called when the creature such as fish and birds excrete the feces and urine from the same orifice?

Unsurprisingly, it’s “excretion.” “Excreta” include both feces and urine. We often use excretion as a synonym for defecation, but this is not strictly correct.

> [@janeslogin](#):
>
> Is there a categorical term for animals that have a cloaca? Is there a taxonomic category for fish, reptiles and birds?

No. In any case, neither “fish” nor “reptiles” are generally recognized as formal taxonomic categories these days. You would just have to say non-mammalian vertebrates (and even this doesn’t include the monotremes, which have cloacas).