Figures

Chapter 6

Fig. 6-1 (above, upper). Passageway between compartments of a social studies enclosure (Figs. 6-8), showing shutter(g), proximity switches (d, magnetic; l, conductive), and arming microswitch (j). Brushing the shutter aside to pass depresses the microswitch lever, closing the circuit that arms the proximity switches.
Fig. 6-2 (above, lower). Water bottle and control assembly for locking and unlocking the shutter that occludes and exposes the water spout. The linear solenoid (l) locks the lightly spring loaded shutter in the closed position until a microswitch lever is pressed (not shown). Pressing the lever energizing the solenoid which retracts and frees the shutter. Printing recorders register the times the shutter opens and closes, etc. The shutter remains unlocked for as long as the animal holds it open while drinking but relocks when the shutter is released, and must be unlocked again to take another drink.

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Fig. 6-3 (above, left). In the upper two graphs are activity correlations (nesting, running, water and food consumption) for a mature female deer mouse for a 1-week period plotted for hourly intervals. Times of abrupt dim light (0.0004 ft-c = 1/3 clear moonless night) and bright light (2 ft-c = 20 lux) presentation are indicated by the positions of the downward and upward facing arrows (5 pm to 6 am). In the lower two graphs are the number of drinks and their avg. lengths.
Fig. 6-4 (above, right). Plots of durations of individual drinks and times between drinks for the same animal and period represented in Fig. 6-3. [< back]

Fig. 6-5. At the left, photo of the extensive laboratory enclosure including complex mazes (see diagrammatic arrangement in Fig. 6-5, right). The bottom of the slanted maze is just visible at the top above the stacked cages. The hardware cloth tubes connect the cages with the vertical-dark maze (lower right), with the vertical transparent maze (lower left), and with the transparent glass and plastic maze (middle left). At the right, simplified diagrammatic arrangement of the cages mazes and gates. Cages containing: dirt (D), dirt and an inverted pan (DP), activity wheel (W), nest (N), food and water (FW), and glass tubes (T). Mazes: vertical-transparent (VT), vertical-dark (VD), and glass-plastic-slanted (T, GP, and S). Unmarked cages were empty. The circled numbers are the positions of the 21 gates.

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Fig. 6-6. Hardware cloth enclosure containing 'wheels' and two deer mice. The 10" wheel with hurdles is in the foreground, with the 6" round, 7" square, and plane 10" wheel in sequence behind it. In the Nature paper a smooth plastic lining replaced the hurdles in the 10" wheel.

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Fig. 6-7. At the left; activity profiles for a deer mouse in the enclosure of Figs. 2-11 & 2-12 on one prior week of water (first set of bars labeled "before"), 3 days on 25% ethanol (open blocks), and one subsequent week on water (second set of bars labeled "after"). The quantities plotted represent the totals for each hour of the day for a 1-week period. The night period (dim light) begins abruptly at 5 pm (downward-pointing arrows) and ends at 5 am (upward-pointing arrows. At the right, drinking profiles and distributions for the same animal and regime as at the left. Results discussed in text.

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Fig. 6-8. At the top, photo of the fully instrumented enclosure employed for studying social interactions between two WF mice. At the bottom, schematic floor plan and components of the enclosure. The food-pellet dispenser (upper left at top) is not shown. The program switch and nest 2 were not used.

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Fig. 6-9. Portion of an 18-channel event record of the activities of the two females in consort in enclosure of Fig. 6-8. Marks on both proximity switch and passage shutter channels indicate passages of mouse #13, those on the passage-shutter channel alone indicate passage of mouse #8. Solid blocks indicate continuous actuation of monitoring channels (e.g., nest 1 occupancy); open blocks indicate repetitive discharges too frequent to be resolved (e.g., wheel rotations).

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Fig. 6-10 (above, left). Time spent in and out of the nest for the two female mice in consort compared with that living solitarily. In the bottom graph the time spent out of the nest for mouse #13 is shown for both the periods before and after consort showing predominant resumption of solitary nesting habits (out of the nest most of the active period when alone, but very much less so when in consort).
Fig. 6-11 (above, right), Combined activity patterns in which the sums of the separate activities of the two female mice living solitarily are compared with the totals living in consort, showing the effects of social interactions. Downward pointing arrows signify initiation of dim light (0.0004 ft-c = 1/3 clear moonless night), upward-pointing arrows, resumption of bright light (2 ft-c = 20 lux).

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Fig. 6-12. Lorenz's sketch of 6 phases of a wild house mouse (Mus musculus) running [fast walking] in a wheel with 4 spokes, as described in text. Labels: phases 1 and 2, rotation accelerating; phase 3, decelerating; phase 4, decelerating; phases 5 and 6, accelerating.

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Fig. 6-13. Walter Sullivan's illustration of four of our running 'wheels' of different design and differing performance parameters in each, for white-footed mice, for his article "Why do mice run?" in The New York Times, Jan. 30, 1966.

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Fig. 6-14. At the left, distributions of numbers of time visited (bars) and total time spent (blocks) at various illumination levels by 4 deer mice (numbered 1 and 2 at top, 3 and 4 at bottom, from left to right) having bidirectional control (by pressing levers) over the levels (see text); open circles, level of full moon, open stars, level of clear moonless night. At the right, the total time subdivided into time spent running (bars) and not running (open blocks) at the various illuminance levels for deer mice #3 (left) and #4 (right) on the same light regime as at the left. Note the greatly different preferences of the two individuals: male #3 greatly preferred the levels clear moonless night to full moon; female #4 greatly preferred clear moonless night and one level greater (0.003 ft-c) but practically avoided running in full moon (only about 5% compared to about 24% for mouse #3).

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Fig. 6-15. Photographs of wheel-running activity patterns of an old-field mouse on six consecutive nights. Each dot gives the instantaneous speed and direction of running (horizontal excursions) as sensed by a tachometer generator attached to the wheel axle, as sampled at 3-sec intervals. Dots to the right of center denote westward running; dots to the left denote eastward running. Central dots indicate a stationary wheel. The horizontal scale is linear, with the 66 rev/min point indicated on Nov. 14. Time is marked off in the margins in 30-min intervals running from bottom to top and beginning at the time when running began. A 1-hr simulated dusk is indicated by the arrows at the lower right for each day. Natural dawn began at the time indicated by the base of the arrows at the upper right; the length of the arrows denotes only its first hour. The curved brackets at the upper left indicate the high-speed running response evoked by natural dawn. The mouse did not always run at high speed during simulated dusk in the fashion more or less typical of WF mice (see Figs. 4-6, 6-17, 6-19 & 6-22), including other old-field mice (the speed depends on the light level during dusk when running begins, which for this mouse was at unusually variable times) . Note that, although the running direction-reversals for Nov. 15 and 16 occur largely within a matter of seconds of the same elapsed times after starting, the absolute times of reversals (clock times) differ by many minutes .

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Fig. 6-16 (above, upper left). Photograph of a typical running record with warm-up for an adapted canyon mouse in dim light (0.0002-0.0009 ft-c) beginning at the time (indicated at the right) of abruptly dimming the light and ending at the time of abruptly brightening them. Hourly intervals are marked by the horizontal center lines running up the vertical axis. Dots to the right represent running away from the artificial moon. (westward), dots to the left, facing the moon (eastward). Central dots indicate no rotation.
Fig. 6-17 (above, middle left). Photograph of a running record of a captive-born canyon mouse on a night using simulated twilights and alternating the position of the 'moon' every hour. The arrow at the lower right indicates the early burst of high-speed duck running (very brief for this mouse). The positions of the 'moon,' dawn, and dusk markers indicate their directions with respect to the direction of running.
Fig. 6-18 (above, lower left). Running record of a cactus mouse illustrating reversal of orientation of polarity to the twilight 'sun,' but not to the 'moon.' The records is for the sun's first night of constant color-temperature twilight changes and different location (further away) after six nights of variable color-temperature changes at the near location. The mouse, which previously oriented away from all light sources, continued to do so with respect to the 'moon,' but reversed orientation to the twilight sun. After several days of this reversal of direction, the mouse gradually resumed its previous twilight orientation (away from the sun).
Fig. 6-19 (above, right). Records of a cactus mouse comparing the first 2 h of running with warm-up on the last night of abrupt presentations of dim light (bottom) with running during the simulated dusks of the six following nights (second to seventh records). Records during the third and fourth simulated dawns (Feb. 23 and 24) are shown in the top. The tips of the arrows at the left mark 25 min into the twilight transitions. Central horizontal lines mark off 30-min, 60-min, and 120-min intervals. All light sources were to the right. Note that instead of an evident warm-up, as in dim light, the mouse began running at high speed during the middle of all six dusks and subsequently slowed (see, also, Fig. 6-22). When running during dawn (Feb. 23 and 24), it sped up to a maximum rate and then ceased abruptly (see, also, Fig. 6-22).

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Fig. 6-20 (above, left). Effects of stepwise alternation of illumination every 30 min on running of a canyon mouse that oriented away from the light. A 3-hr period consisting of two 90-min periods of dim-dimmer-dimmest light presentations (with different illumination levels used on each night) is shown from records from three successive nights. The dimmest level on Jan. 19, when very little running occurred, was darkness.
Fig. 6-21 (above, right). Quantitative plots of the canyon mouse's 30-min running responses pictured in Fig. 6-20 (but for the entire night), including time spent running, number of revolutions, average rpm, average session lengths, and orientational consistency.

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Fig. 6-22 (above, left). Running and nesting responses of a male canyon mouse to simulated 1-hr dusks and dawns (variable color temperature) presented in immediate succession, beginning with a dusk at the usual time. Two hours of dim light were presented after the third dusk. This animal oriented very consistently toward the 'moon' and twilight 'sun.' Centerline at left, with time in nest to left of centerline. Responses are described in detail in the text.
Fig. 6-23 (above, right). Wheel running of a Florida mouse on a bright-dark regime (lights turned off at 19:00 h and on 04:00 h. The running record is for the ninth night of this regime. Note the typical (but bidirectional) warm-up, the relatively unsustained bidirectional running pattern in the dark, and the spurts of high-speed running when the bright lights came on. The latter are reminiscent, though much less pronounced, of those during simulated and natural twilights just before activity ceases abruptly (see Figs. 6-15, 18, 19 & 22).

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Fig. 6-24. Responses of a canyon mouse when frictional torque was applied to the wheel axle alternately in opposite directions every 30 min (indicated by absence of "F" for free). Four hours are shown for Apr. 1-3, 6 h, 30 min for Apr.4, 6, 7, and 6 h for Apr. 9. Relative torque values are indicated by the applied voltage (indicated adjacent to date). Note the relatively poor performance on Apr. 1, as the animal adapted to the new program, maintaining slower unidirectional running at 48% against the clutch (3.5 v). Time spent in unidirectional running increased on Apr. 2, but more slowly and only at the 43% level against the clutch (5 v). Both running parameters decreased on Apr. 3 with only 41% against the clutch (5.5 v). By Apr. 4 the performance deteriorates further, with both running reversals and only 31% running, but very slowly, against the clutch (7 v). The performance was the same on Apr. 5. On Apr. 6 there was only 5.7% very slow running against the clutch (8 v), with the mouse reversing direction significantly rather than cease entirely. On Apr. 7 the mouse was virtually unable (only 1.4%) to run, again very slowly, against the clutch (16 v), instead reversing direction rather consistently. The performance was the same on Apr. 8. With a return to a voltage of 4.5 on Apr. 9, the mouse returned to a high degree (50%) of running against the clutch, although more slowly and with a new preference for running in the opposite direction at over the 99% level.

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