'Ghost' moose observations reported in northern Idaho

The Idaho Department of Fish and Game (IDFG) Panhandle office is again starting to receive calls about odd looking moose. The moose appear to be partially white; or, as one person reported, Ôghost-like' in appearance. Moose can experience tick infestations that start in mid-September but the problem is not clearly visible to people until late in the following winter. The ticks are called "moose ticks". Less commonly they are referred to as "winter ticks". The infestations become visible when moose scratch and paw at their own skin enough to cause large patches of hair to break or fall out. That is when IDFG begins to get reports of sick looking moose. Many times these patches are on the withers where moose are able to reach and scratch with their hooves. The skin that is exposed by the hair loss is light colored. From a distance, the exposed skin makes the moose appear to be white in color. Moose tick larvae hatch from eggs laid on the ground in April. They climb vegetation during the late summer and early fall and wait for a moose to come along. Stimulated by the carbon dioxide exhaled by a moose, they interlock their legs and wait. When a moose contacts the brushy vegetation covered by interlocked tick larvae, strings of thousands of tick larvae cling onto the hair of the moose and crawl toward the skin. These tick larvae can also cling to deer, however, deer appear to be able to scratch them off. Infested moose average 33,000 ticks, and one dead moose was documented to have over 100,000 ticks. Pity the biologist who had to count them! Moose ticks take a blood meal from their host in November, January, March and April. In April, the female ticks drop off to lay their eggs on the soil surface, starting the tick life cycle over again. When female ticks drop off a moose and onto snow, many do not survive. When moose ticks drop off and fall onto bare ground, their survival rate and reproduction is much higher. Therefore, heavy or late winters reduce tick infestations the following fall/winter. Mild winters where most or all of the snow is gone by April lead to higher infestations to follow. Thousands of feeding ticks are potentially fatal to moose. While some moose survive until the ticks fall off and subsequently recover, some moose die. The cause of mortality can be loss of blood, hypothermia due to loss of hair, or starvation when the severe itching causes them to forage less than necessary. Mortality is highest in calf moose. Their smaller body mass loses heat more readily. It has been estimated that calves can potentially lose an estimated half of their blood to the attached ticks. Ticks are absent from moose by late May and into September, when new larvae may attach again. Fortunately for people, moose ticks do not use humans as a host. This particular tick will not attach to a human, however, a moose infested with them can become so agitated that the moose becomes aggressive toward people to the extent the moose poses a potential danger. If you see a Ôghost moose', stay away. The stressed and irritated moose may become aggressive toward people and could cause severe injury or even death to a person.