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[thesaddlepatch]

Reproductive Conflict and the Evolution of Menopause in Killer Whales

Why females of some species cease ovulation prior to the end of their natural lifespan is a long-standing evolutionary puzzle [1, 2, 3, 4]. The fitness benefits of post-reproductive helping could in principle select for menopause [1, 2, 5], but the magnitude of these benefits appears insufficient to explain the timing of menopause [6, 7, 8]. Recent theory suggests that the cost of inter-generational reproductive conflict between younger and older females of the same social unit is a critical missing term in classical inclusive fitness calculations (the “reproductive conflict hypothesis” [6, 9]). Using a unique long-term dataset on wild resident killer whales, where females can live decades after their final parturition, we provide the first test of this hypothesis in a non-human animal. First, we confirm previous theoretical predictions that local relatedness increases with female age up to the end of reproduction. Second, we construct a new evolutionary model and show that given these kinship dynamics, selection will favor younger females that invest more in competition, and thus have greater reproductive success, than older females (their mothers) when breeding at the same time. Third, we test this prediction using 43 years of individual-based demographic data in resident killer whales and show that when mothers and daughters co-breed, the mortality hazard of calves from older-generation females is 1.7 times that of calves from younger-generation females. Intergenerational conflict combined with the known benefits conveyed to kin by post-reproductive females can explain why killer whales have evolved the longest post-reproductive lifespan of all non-human animals.

Source

[thesaddlepatch]

Bless u for this blog. Also hope you don't mind me reblogging a ton of your stuff until I have time to post my own original content?

Of course not! Please let us know if any of the links are broken if you encounter any 😊

[thesaddlepatch]

Localizing Vocalizations in southern resident killer whales: A look at Gender Differences

The southern resident killer whales (Orcinus orca), known as J, K, and L pods, forage in the inland and coastal waters of Washington State and British Columbia. The social and acoustic associations characterize the relatedness of this population. A pod is a primary social unit made up of stable matrilines that associate regularly (>50% of observation time), and emigration of males or females hasn’t been observed (Yurk et al., 2002). These stable kin groups are believed to share a unique repertoire of discrete call types; and pods that are acoustically related and share parts of these vocal traditions are called an acoustic clan (Ford, 1991). A community is when pods have frequent associations with one or more pods and have different distributions in relation to other communities (Ford, 1987). Hence, J, K, and L pods socially make up the southern resident community (about 90 whales) and are acoustically know as the J clan, distinguishing them from the northern resident community of 16pods (about 200 whales) and acoustically known as A, G, and R clans (Ford 1991

Link

[thesaddlepatch]

Echolocation signals of free-ranging killer whales and modeling of foraging for chinook salmon

Fish-eating ‘‘resident’’-type killer whales ~Orcinus orca! that frequent the coastal waters off northeastern Vancouver Island, Canada have a strong preference for chinook salmon. The whales in this region often forage along steep cliffs that extend into the water, echolocating their prey. Echolocation signals of resident killer whales were measured with a four-hydrophone symmetrical star array and the signals were simultaneously digitized at a sample rate of 500 kHz using a lunch-box PC. A portable VCR recorded the images from an underwater camera located adjacent to the array center. 

Link

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Aspects of growth in captive Killer Whales

Morphometrics from 25 captive killer whales (11 captive-born) were collected at SeaWorld parks from 1984 to 1995 to determine age-specific growth parameters. For sexes combined, the body-volume index was the most accurate predictor of body weight. However, predicting weight from total length was appropriate, although it may underestimate weight of pregnant animals. Among captive-born calves, a Gompertz model was the best predictor of weight and length at age. Estimates for length and weight at birth were done using data from in utero and neonatal calves. For ages 1-5 yr, models indicate that males grew in both weight and length at slower rates. Growth rates in males may surpass those of females at approximately 5-6 yr of age.

Link

[thesaddlepatch]

Killer whale reproduction at Sea World

Sea World has maintained killer whales (Orcinus orca) since 1965. The total killer whale inventory (1965–1993) has included 39 whales (25 females, 14 males); 28 were wild-caught and 11 captive-born, including one second-generation calf. As of September, 1993, there were 19 whales in the breeding program. Ten of these whales (53%) were captive-born, either at Sea World or other facilities in North America. The live wild-caught whales ranged in estimated age from 12–27 years (x̄ ± sd = 17.6 ± 4.2 years). The captive-born whales ranged in age from <1 to 8 years. In the Sea World breeding program (through September, 1993), there have been nine live births and one stillbirth, with eight calves part of the current inventory. Births occurred from July to February. Calving intervals ranged from 32–58 months. Female age at birth of first calves ranged from 8 years to an estimated 17 years (x̄ ± sd = 12.7 ± 3.0 years). Gestation, based on conception estimates from serum progesterone analysis, averaged 17 months (x̄ ± sd = 517 ± 20 days), but successful pregnancies with viable calves occurred from 15–18 months (468–539 days). Females, in the presence and absence of males, were polyestrus with periods of cycling interspersed with individually variable noncycling (presumed anestrous) periods ranging from 3–16 months. 

Link

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Space Use Patterns and Population Trends of Southern Resident Killer Whales in Relation to Distribution and Abundance of Pacific Salmon

Killer whales (Orcinus orca) are long-lived top predators occurring in relatively low densities throughout their range (Dahlheim and Matkin 1994). As such, they have been viewed as indicators of ecosystem health and have become the focus of intensive study (Heimlich-Boran 1986). A population of killer whales in the Northeast Pacific, known as the southern resident community (SRC), has drawn considerable interest due to its proximity to urban areas, a long-term survey program on the population, and a recent decline in numbers that has led to the listing of the SRC as an Endangered Species under the US Endangered Species Act of 1973 as amended (ESA), the Canadian Species at Risk Act (SARA), and Washington State law (Baird 2001; Wiles 2004; NMFS 2005). A number of factors have been identified as possible causes in the recent decline of the SRC, including anthropogenic disturbance, high concentrations of contaminants, and a reduction in quality or quantity of preferred prey (Baird 2001; Krahn et al. 2002; Wiles 2004). This study investigates the relationship between the SRC and Pacific salmon (Oncorhynchus spp.) to better understand prey associations and to provide useful information for management actions. Link

[thesaddlepatch]

Comparing Vocalizations between Matrilines of Southern Resident Killer Whales

Vocalizations are an important part of the killer whale (Orcinus orca) species used in all aspects of their lives; communication, foraging, and traveling. It has been suggested that killer whales have different dialects to differentiate from one other, at least on the pod or matrilineal level. The goal was to identify a whale to a call and compare the calls across matrilines within the three Southern Resident killer whale pods. This proved difficult not having enough data to accurately make assumptions. But some evidence provided that there could be vocal learning in social situations between pods in the past couple decades, this could also supported due to the fact that the three southern resident pods (J K &L, making up J clan) have been starting to intermingle more in the most recent years. I was also about to see pod call structure similarities. Link

[thesaddlepatch]

Magic?

Food consumption and suckling in Killer whales

Between 1976 and 1996 food consumption and suckling in Killer whales Oscines orca maintained at Marineland Antibes, France, were studied. The food intake of the whales was still increasing at 20 years of age, when they were consuming c. 19 000 kg of fish per year. Wild Killer whales will expend more energy foraging than captive animals and probably eat more than 19 000 kg/year. A seasonal pattern of food consumption was observed in all the whales, although this may have been caused by seasonal changes in the feeding schedule. Data on the number of suckling bouts per 24 hours in the first 5–10 days after birth of 1.1 calves are presented, together with the body measurements of a 13 year-old male.

Link

[thesaddlepatch]

Food consumption and suckling in Killer whales

Between 1976 and 1996 food consumption and suckling in Killer whales Oscines orca maintained at Marineland Antibes, France, were studied. The food intake of the whales was still increasing at 20 years of age, when they were consuming c. 19 000 kg of fish per year. Wild Killer whales will expend more energy foraging than captive animals and probably eat more than 19 000 kg/year. A seasonal pattern of food consumption was observed in all the whales, although this may have been caused by seasonal changes in the feeding schedule. Data on the number of suckling bouts per 24 hours in the first 5–10 days after birth of 1.1 calves are presented, together with the body measurements of a 13 year-old male.

Link

[thesaddlepatch]

Hello! You know where to get the PDF of Killing Keiko?

Sorry we no longer hold a link to that pdf

[thesaddlepatch]

EU Zoo Inquiry

A review of the keeping of whales and dolphins in captivity in the European Union and EC Directive 1999/22, relating to the keeping of wild animals in zoos.

Link

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Ingrid Vissers presentation at the Coastal Commission vote on the Blue World Project. 08/10/2015

[thesaddlepatch]

Are you pro-cap, anti-cap or a mix of the two?

This page is run by @cute-whales, @fachaich , @coffeeandkudzu and @stumpyx163. We are all anti-captivity but run this blog as a database of information for all.

[thesaddlepatch]

Do you have sources proving that Ruffles isn't Granny's son? And any sources disproving her supposed age of 100+ years? Thanks.

Yes we do: RP102Inferred Paternity and Male Reproductive Success in a Killer Whale (Orcinus orca) Population It’s a complex read but in the tables it lists J1′s parents as ‘unsampled’ when J2 was sampled in the study. Otherwise for data disproving her age I again refer to the above paper where it states:“The other (Uns-M6) was inferred to be the father of one old individual (J2) and one young individual (K38) and there were no males in the population old enough to have sired both of these individuals, suggesting that this inferred paternal sibling relationship was spurious or perhaps caused by some other relationship between the 2 individuals.“  (K38 born 2004.)It’s not proof but it throws doubt. I am unsure why the paper turns to another explanation besides them sharing a father continuing with J2 being much older but there you go anon- all the data we have. 

[thesaddlepatch]

Necropsy- Killer Whale Canuck II

Necropsy (autopsy) of deceased captive killer whale (Orcinus-orca) Canuck II at SeaWorld, San Diego, CA, U.S.A.

Link 

[thesaddlepatch]

Necropsy- Killer Whale Canuck

Necropsy (autopsy) of deceased captive killer whale (Orcinus-orca) Canuck at SeaWorld, Orlando, FL, U.S.A. Link