biology

Hydrochoerus

Hydrochoerus is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hydrochoerus rather than just read about it. In short: The genus Hydrochoerus contains two living (the lesser and greater capybaras) and three extinct species of rodents from South America, the Caribbean island of Grenada, California and Panama. Capybaras are the largest living rodents.

Key takeaways

Hydrochoerus belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hydrochoerus to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hydrochoerus from memory before moving on to harder problems.

Reference excerpt

The genus Hydrochoerus contains two living (the lesser and greater capybaras) and three extinct species of rodents from South America, the Caribbean island of Grenada, California and Panama. Capybaras are the largest living rodents. The name of the genus is derived from Ancient Greek ὕδωρ (húdor), meaning "water", and χοῖρος (khoîros), meaning "pig".

Characteristics Capybaras are semiaquatic, found in and near lakes, rivers, swamps, and flooded savanna. Their diets are dominated by grasses. Adults weigh up to 65 kg (143 lb). The gestation period is 130–150 days, with two to eight (most commonly four) young born to females.

Behavior Capybaras are highly social, living in groups of up to 100 and communicating through a variety of vocalizations. Breeding is polygynous, with males forming harems.

Phylogeny and taxonomy Molecular results have consistently suggested Hydrochoerus is most closely related to Kerodon (the rock cavies), and the two evolved from within the Caviidae. This led Woods and Kilpatrick to unite the two into the subfamily Hydrochoerinae within the Caviidae. Based on use of a molecular clock approach, Hydrochoerus appears to have diverged from Kerodon in the late Middle Miocene (about 12 million years ago). The extinct North American species formerly recognized as Hydrochoerus holmesi is now assigned to Neochoerus.

Species

Extant Species

Fossils † Hydrochoerus ballesterensis – Pliocene capybara endemic to Argentina † Hydrochoerus gaylordi – Plio-Pleistocene capybara endemic to the Caribbean island of Grenada † Hydrochoerus hesperotiganites – Late Pleistocene capybara endemic to North America (San Diego County, California)

Distribution Presently, capybaras live in northern South America and adjacent southern Central America (lesser capybara) and in the tropical to subtropical regions of South America (capybara). The fossil species inhabited Buenos Aires Province in Argentina (H. ballesterensis) and the Caribbean island of Grenada (H. gaylordi). One species, H. hesperotiganites even ranged as far north as California. Fossils of unspecified Hydrochoerus have been found in Late Pleistocene to Holocene sediments of Curití, Santander, at an altitude of 1,500 m (4,900 ft) in the Eastern Ranges of the Colombian Andes. Fauna found at the same site included the South American tapir (Tapirus terrestris), Cryptotis sp., collared peccary (Tayassu tajacu), white-lipped peccary (Tayassu pecari), and Mazama sp.

References

Bibliography Hoffstetter, Robert (1971). "Los vertebrados cenozóicos de Colombia: yacimientos, faunas, problemas planteados" (PDF). Universidad Nacional de Colombia: 37–62. Archived from the original (PDF) on 2017-04-06. Retrieved 2017-04-05. {{cite journal}}: Cite journal requires |journal= (help) Rowe, D.L.; Honeycutt, R.L. (2002). "Phylogenetic relationships, ecological correlates, and molecular evolution within the Cavioidea (Mammalia, Rodentia)". Molecular Biology and Evolution. 19 (3): 263–277. doi:10.1093/oxfordjournals.molbev.a004080. ISSN 0737-4038. PMID 11861886.

Further reading Nowak, Ronald M. (1999). Walker's Mammals of the World, 6th edition. Johns Hopkins University Press. pp. 1–1936. ISBN 978-0-8018-5789-8.

Illustrations

Worked examples

Example 1 — a first encounter with Hydrochoerus

Start with the simplest possible case. Write down what Hydrochoerus claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hydrochoerus before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hydrochoerus ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hydrochoerus

In research: Hydrochoerus appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hydrochoerus in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hydrochoerus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cavies, Fossils of Argentina, Fossils of Colombia, so understanding it makes those chapters shorter.
In everyday life: Look for Hydrochoerus outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hydrochoerus in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hydrochoerus means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hydrochoerus out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hydrochoerus in simple terms?

Why does Hydrochoerus matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hydrochoerus?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hydrochoerus.