Figure 9.—After release, the wolf lay still for 1½ hours before jumping up and running off. (Photo courtesy of L. D. Mech.)
Figure 10.—A radio transmitter collar was placed around the neck of each trapped wolf. (Photo courtesy of D. L. Breneman.)
Figure 11.—Each ear of the wolf was tagged with identifying numbers. (Photo courtesy of Richard Bend.)
Each wolf was examined, outfitted with a radio transmitter collar 15 inches inside circumference ([fig. 10]) and tagged with identification numbers in both ears ([fig. 11]). Each transmitter was of a different frequency in the 150 MHz range, emitted a pulsed signal ranging from 75 to 350 pulses per minute, and had a calculated life of at least 300 days ([fig. 12]). Two types of 12-inch whip antennas were used on the transmitters: one type extended up the side of the collar and then stuck out above for 6 inches; the other was fully attached inside the collar and extended up one side, around the top, and partly down the other side. The transmitter, batteries, and antenna were molded into a collar of acrylic weighing 11 ounces (Mech et al. 1965).[2] All radio equipment functioned flawlessly for at least 5 months, and one transmitter continued operating for at least 9 months.