Editing Cetacea (section)

=== Strandings ===
{{Main|Cetacean stranding}}
A stranding is when a cetacean leaves the water to lie on a beach. In some cases, groups of whales strand together. The best known are mass strandings of [[pilot whale]]s and sperm whales. [[Cetacean stranding|Stranded]] cetaceans usually die, because their as much as {{convert|90|MT|ST}} body weight compresses their lungs or breaks their ribs. Smaller whales can die of heatstroke because of their thermal insulation.{{citation needed|date=October 2024}}
[[File:Ecomare - gestrande bultrug op Razende Bol (bultrug2012-razende-bol-412-sw).jpg|thumb|Beached humpback whale]]
The causes are not clear. Possible reasons for mass beachings are:<ref name="wdcs" />
* toxic contaminants
* debilitating parasites (in the respiratory tract, brain or middle ear)
* infections (bacterial or viral)
* flight from predators (including humans)
* social bonds within a group, so that the pod follows a stranded animal
* disturbance of their magnetic senses by natural anomalies in the Earth's magnetic field
* injuries
* [[Noise pollution#Wildlife|noise pollution]] by shipping traffic, seismic surveys and military sonar experiments

Since 2000, whale strandings frequently occurred following military [[sonar]] testing. In December 2001, the US Navy admitted partial responsibility for the beaching and the deaths of several marine mammals in March 2000. The coauthor of the interim report stated that animals killed by active sonar of some Navy ships were injured. Generally, underwater noise, which is still on the increase, is increasingly tied to strandings; because it impairs communication and sense of direction.<ref>{{cite journal |author=Schrope, Mark. |title=Whale deaths caused by US Navy's sonar |journal=Nature |volume=415 |issue=106 |pages=106 |year=2003  |doi=10.1038/415106a|bibcode = 2002Natur.415..106S |pmid=11805797|s2cid=52827761 |doi-access=free }}</ref>

[[Climate change]] influences the major wind systems and ocean currents, which also lead to cetacean strandings. Researchers studying strandings on the Tasmanian coast from 1920 to 2002 found that greater strandings occurred at certain time intervals. Years with increased strandings were associated with severe storms, which initiated cold water flows close to the coast. In nutrient-rich, cold water, cetaceans expect large prey animals, so they follow the cold water currents into shallower waters, where the risk is higher for strandings. Whales and dolphins who live in pods may accompany sick or debilitated pod members into shallow water, stranding them at low tide.<ref>{{Cite journal |last1=Evans |first1=K |last2=Thresher |first2=R |last3=Warneke |first3=R.M |last4=Bradshaw |first4=C.J.A |last5=Pook |first5=M |last6=Thiele |first6=D |last7=Hindell |first7=M.A |date=2005-06-22 |title=Periodic variability in cetacean strandings: links to large-scale climate events |journal=Biology Letters |volume=1 |issue=2 |pages=147–150 |doi=10.1098/rsbl.2005.0313 |issn=1744-9561 |pmc=1626231 |pmid=17148151}}</ref>