Editing Goose (section)

== True geese and their relatives ==
[[File:Anser caerulescens CT8.jpg|thumb|[[Snow geese]] (''Anser caerulescens'') in [[Quebec]], [[Canada]]]]
[[File:Bütykös lúd - Gergelyiugornya.JPG|thumb|[[Chinese geese]] (''Anser cygnoides domesticus''), the domesticated form of the [[swan goose]] (''Anser cygnoides'')]]
[[File:Geese in Naantali, Finland.jpg|thumb|[[Barnacle geese]] (''Branta leucopsis'') in [[Naantali]], [[Finland]]]]

The two living [[genus|genera]] of true geese are: ''[[Anser (genus)|Anser]]'', grey geese and white geese, such as the [[greylag goose]] and [[snow goose]], and ''[[Branta]]'', black geese, such as the [[Canada goose]].

Two genera of geese are only tentatively placed in the Anserinae; they may belong to the [[shelduck]]s or form a subfamily on their own: ''[[Cereopsis]]'', the Cape Barren goose, and ''[[Cnemiornis]]'', the prehistoric [[New Zealand goose]]. Either these or, more probably, the goose-like [[coscoroba swan]] is the closest living relative of the true geese.

[[Fossil]]s of true geese are hard to assign to genus; all that can be said is that their fossil record, particularly in [[North America]], is dense and comprehensively documents many different species of true geese that have been around since about 10 [[million years ago]] in the [[Miocene]]. The aptly named ''Anser atavus'' (meaning "progenitor goose") from some 12 million years ago had even more [[plesiomorph]]ies in common with swans. In addition, some goose-like birds are known from [[subfossil]] remains found on the [[Hawaiian Islands]].

Geese are [[Monogamous pairing in animals|monogamous]], living in permanent pairs throughout the year; however, unlike most other permanently monogamous animals, they are territorial only during the short nesting season. Paired geese are more dominant and feed more, two factors that result in more young.<ref>{{cite journal |last=Lamprecht |first=Jürg |title=Female reproductive strategies in bar-headed geese (''Anser indicus''): Why are geese monogamous? |journal=Behavioral Ecology and Sociobiology |volume=21 |issue=5 |pages=297–305 |publisher=Springer |year=1987 |doi=10.1007/BF00299967|bibcode=1987BEcoS..21..297L |s2cid=34973918 }}</ref><ref>{{Cite web|date=10 May 2011|title=Canada Goose|url=https://www.nationalgeographic.com/animals/birds/c/canada-goose/|archive-url=https://web.archive.org/web/20170502042921/http://www.nationalgeographic.com/animals/birds/c/canada-goose/|url-status=dead|archive-date=May 2, 2017|access-date=21 November 2020|website=National Geographic|language=en}}</ref>