Wild Babies VERIFIED Download
In this second book in the West Coast Wild series, readers will meet the baby animals born in the pristine wilderness of the Pacific west coast, including land and marine mammals, fish, birds and amphibians. --> In this second book in the West Coast Wild series, readers will meet the baby animals born in the pristine wilderness of the Pacific west coast, including land and marine mammals, fish, birds and amphibians.
Wild Babies download
In this second book in the West Coast Wild series, readers will meet the baby animals born in the pristine wilderness of the Pacific west coast, including land and marine mammals, fish, birds and amphibians.
In Europe and Asia, predation by natural predators can account for up to 25% of annual mortality at the population level (16). In the United States, however, humans are the most significant predator of wild pigs (5). Though predators such as coyotes (Canis latrans), bobcats (Lynx rufus), and golden eagles (Aquila chrysaetos) may opportunistically prey upon immature wild pigs; it is only where wild pigs exist with American alligators (Alligator mississippiensis), mountain lions (Puma concolor), and black bears (Ursus americanus) that any frequent intentional predation of the species may occur (17-19). Even where this type of predation does occur, it plays a minor role in wild pig mortality (5).
The age at which reproductive maturity is reached is highly variable among populations of wild pigs (20). Males have been documented to reach sexual maturity by five months of age and have been observed attempting to breed at six months. However, breeding success is strongly correlated with size (20, 21). Thus, males are not typically successful in breeding until 12 to 18 months of age (18). Reproductive maturity has been documented in female wild pigs as early as three months of age, though successful first breeding is generally reported to occur between the ages of 6 and 10 months (18, 22). As with males, female reproductive maturity is also correlated with size. Researchers have found that females did not reach reproductive maturity until they reached approximately 100-140 lbs (22).
Pigs have the highest reproductive rate of any ungulate; but like reproductive maturity, it is highly variable among populations (23-25). Females (sows) have multiple estrous cycles annually and can breed throughout the year with an average litter size of 4-6 young per litter (5). The average gestation period for a sow is approximately 115 days and they can breed again within a week of weaning their young, which can occur approximately one month after birth (26, 27). Though it is a physiological possibility for a sow to have three litters in approximately 14 months (28), researchers found that in southern Texas adult and sub-adult sows averaged 1.57 and 0.85 litters per year, respectively (25). Birthing events can occur every month of the year, though most wild pig populations exhibit prominent peaks in birthing events that correlate with forage availability (25, 29) with peaks generally occurring in the winter and spring months (30). In areas where forage is not a limiting factor, such as lands in cultivation or where supplemental feeding for wildlife is common practice, reproduction rates can be higher than average (31).
Wild pigs are omnivores, generally categorized as opportunistic feeders, and typically consume between 3% and 5% of their total body mass daily (32). They exhibit a generalist diet consuming a variety of food sources which allows them to thrive across a wide range of environments (1, 10, 33). Throughout their range their diet is mostly herbivorous, shifting seasonally and regionally among grasses, mast, shoots, roots, tubers, forbs, and cacti as resource availability changes (4, 30, 34). When available, wild pigs will select for agricultural crops, often making up over 50% of the vegetative portion of their diets and causing significant damage to agricultural fields (35, 36). Invertebrates are often consumed while foraging for vegetation throughout the year including insects, annelids, crustaceans, gastropods, and nematodes (37). Studies have shown that, in some cases, invertebrates are highly selected for and seasonally make up over 50% of wild pig diets (38, 39). Wild pigs will also consume tissues of vertebrate species through scavenging and direct predation (37, 40, 41). Studies have documented intentional predation of various vertebrate species by wild pigs including juvenile domestic livestock, white-tailed deer (Odocoileus virginianus) fawns, ground nesting bird nests (Galliform sp.), and various species of reptiles and amphibians (41-43, 97, 98).
Wild pigs have been listed as one of the top 100 worst exotic invasive species in the world (44). In 2007, researchers estimated that each wild pig carried an associated (damage plus control) cost of $300 per year, and at an estimated 5 million wild pigs in the population at the time, Americans spent over $1.5 billion annually in damages and control costs (45). Assuming that the cost-per-wild pig estimate has remained constant, the annual costs associated with wild pigs in the United States are likely closer to $2.1 billion today (10, 11, 45).
Most damage caused by wild pigs is through either rooting or the direct consumption of plant and animal materials (5). Rooting is the mechanism by which wild pigs unearth roots, tubers, fungi, and burrowing animals (5, 46). They use their snouts to dig into the ground and turn over soil in search of food resources, altering the normal chemistry associated with nutrient cycling within the soil. Further, the mixing of soil horizons that often accompanies rooting by wild pigs has also been shown to alter vegetative communities, allowing for the establishment and spread of invasive plant species (33). It has been estimated that a single wild pig can significantly disturb approximately 6.5 ft2 in just one minute (47). This large-scale soil disturbance can increase soil erosion rates and have detrimental effects to sensitive ecological areas and critical habitats for species of concern (41, 48, 49). When wild pigs root or wallow in wetland or riparian areas, it tends to increase the nutrient concentration and total suspended solids in nearby waters due to erosion (48, 50).
Wild pigs also directly contribute fecal coliforms into water sources, increase sedimentation and turbidity, alter pH levels, and reduce oxygen levels (51, 52). Such activities lead to an overall reduction in water quality and degradation of aquatic habitats. Impacts from wild pigs are positively correlated with population density and vary in severity among ecosystems. Native habitat degradation as well as loss of biodiversity and ecosystem services caused by wild pigs are difficult to quantify and impossible to fully assign monetary value. However, monetizing such damage would undoubtedly increase the estimated costs associated with the species (35).
Economically, wild pigs have the greatest impact on the agricultural industry in the United States (2). In 2005, researchers estimated that in a single night, one wild pig can cause at least $1,000 in damages to agriculture (53). In Texas, a 2006 publication reported that wild pigs caused approximately $52 million in agricultural damage annually (54). More recent studies published in 2016 and 2019 estimate that the annual loss to agriculture in Texas is approximately $118.8 million (95, 96). Impacts to crops are not limited to direct consumption. Trampling of standing crops and damage to soil from rooting and wallowing activities account for 90-95% of crop damage, in some cases (55). Standing crops are not the only form of agriculture damaged by wild pigs. Wild pigs also cause damage to hay fields, orchards, farming equipment, and fences.
The human population of the United States is rapidly growing, and the majority of that population lives in urban areas. In general, the resulting expansion of urban sprawl has increased human-wildlife interactions (62). That trend along with the recent population growth and range expansion of wild pigs has resulted in an increase in damage to private property and common recreational areas (5). Wild pigs often seek out food and water in residential areas during times of drought which leads to damage of landscaping, fencing, and irrigation systems in residential areas as well as communal areas such as golf courses and parks (5, 63, 64). In addition, wild pig-vehicle collisions can result in significant property damage as well as human injury and death (56). Researchers conservatively estimated damages associated with wild pig-vehicle collisions to be $36 million annually in the United States alone (67). Because projections show rapid expansion of both human and wild pig populations the frequency of wild pig-vehicle collisions will likely increase, as well (65). Not only do wild pigs physically damage natural resources and agricultural crops, personal property, and equipment, they also have a high potential to transmit various diseases to domestic livestock (56).
Wild pigs are capable of carrying and transmitting at least 30 bacterial, fungal, and viral diseases which threaten humans, livestock, and wildlife (7, 57). Some of those which can infect humans are brucellosis, leptospirosis, toxoplasmosis, and trichinosis (58). Though disease transmission to humans is a real concern, the largest threat from wild pig diseases is the potential transmission to domestic livestock. Diseases such as swine brucellosis, pseudorabies, classic swine fever, and African swine fever can result in birth defects and death of various livestock and wildlife species (7). Diseases such as classic swine fever and foot and mouth disease have been eradicated from the United States pork industry and are considered foreign-animal diseases. Wild pigs, however, have the potential to act as a reservoir for these diseases making it difficult or impossible to eradicate them again in areas with infected wild pig populations (59). A scenario where one of these diseases is reintroduced could cause crippling damage to the United States agricultural industry (7, 60). One extreme scenario is the reemergence of foot and mouth disease in the United States. If this disease were to be reintroduced to the domestic livestock industry, it could cause up to $21 billion in loss of agricultural income and a portion of small farmers to lose their farms (61). For more information on diseases transmissible to humans, domestic animals and wildlife, please see Diseases of Feral Swine (PDF).