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The Dolphin Institute - Dolphin Research Summaries
Alaska is a better measure of current reproductive rates. A comparison of this estimate with historical estimates of pregnancy rated from whaling records provides no evidence of a marked density dependent increase in the reproductive rate of humpback whales. Baker, C. S., Perry, A., and Herman, L. M. (1987). Reproductive ...
www.dolphin-institute.org

ITEC Faculty
I conducted a long term study of life history and behavior of bottlenose dolphins in Australia, who, like humans, have very slow reproductive rates, heavy maternal investment in single offspring, extensive male-male cooperation, and very large relative brain sizes. Unlike humans they have no male parental investment. Dolphins thus show convergent ...
www.itec-edu.org

US Navy's Misinformation to Congress About LFAS
Navy's planned deployment levels. Fact - After testing LFAS for only one month the impact on long term reproductive rates of whales, dolphins, fish and all marine life are not known. Fact - The Marine Mammal Commission, (a federal agency created to help protect marine mammals), expressed grave concerns in their 1997 annual report to Congress ...
www.oceanmammalinst.org

SCS: Ringed Seal (Phoca hispida)
Hunting reduced the population size to about 25,000 in the 1940s, while reproductive failure caused numbers to crash to about 10,000 in the 1970s. Hunting of the ... to the health of the ringed seal population. Pollution-caused uterine occlusions, which severely reduce reproductive rates and which are probably caused by organochlorines such as PCBs, peaked at the end of ...
www.pinnipeds.org

2007 IUCN Red List – Search
Arctic marine environment. Polar bears exhibit low reproductive rates with long generational spans. These factors make facultative adaptation by polar bears to significantly ... fail to reproduce more often and give birth to smaller young that have higher mortality rates. Polar bears may be forced on shore for extended periods and rely on fat reserves ...
iucnredlist.org

Polar Bear - Defenders of Wildlife
November through January while the mothers are hibernating. Cubs will remain with their mothers for at least 2 ½ years. Female polar bears can produce five litters in their lifetime, which is one of the lowest reproductive rates of any mammal. Threats Climate change, which is causing the loss of older stable sea ice and the thinning, disappearance and ...
defenders.org

The Delta News
If dispersal rates are tied to habitat conditions, then this pattern also supports the role of dispersal as ... : 347-351. Koons, D.N. and J.J. Rotella. 2003. Have lesser scaup, Aythya affinis, reproductive rates declined in parkland Manitoba? Canadian Field-Naturalist 117:582-588. Larivière, S. 2003. Edge ...
deltawaterfowl.org

EcoFuture (TM) Population and Sustainability - Reference Material
Yet it takes a generation for numbers to level off once there is a reduction in reproductive rates. Without increased numbers from mass immigration, the U.S. population would stabilize at 247 million by ... a billion in 2050, according to the U.S. Census Bureau. This means that with continued immigration rates, U.S. population will possibly double within the next 50 years. From the point of view of ...
ecofuture.org

Kangaroo rat, Dipodomys ordi, control and management
October in southern desert states. The breeding period is shorter in the northern states. The gestation period is approximately 30 days. Reproductive rates vary according to species, food availability, and density of rodent populations. Females have 1 to 3 litters of 1 to 6 young per year. The young are born hairless and blind in a fur-lined nest ...
icwdm.org

Jackrabbit, Lepus californicus, L. townsendii, L. americanus, control and biology information
Females may produce up to 4 litters per year with 2 to 8 young per litter. Reproductive rates may vary from year to year depending on environmental conditions. Where food and shelter are available in one place, no major daily movement of hares occurs. When food areas and shelter areas are separated, morning and evening ...
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