Comparison of activity trackers in estimating canine behaviors

Figures & data

Table 1. Information about the activity trackers used in the experiment and their placement in this study.

Device	Placement	Dimensions	Weight	Company	City, Country
Kaunila^a	neck	∅ 3.6 cm × 1 cm	10 g	Kaunila Oy	Kuopio, Finland
FitBark (1st version)	neck	4.1 × 2.8 × 1.1 cm	7 g	FitBark Inc	Kansas City, Missouri, USA
ActiGraph GT9X Link	neck and back	3.5 × 3.5 × 1 cm	14 g	ActiGraph LLC	Pensacola, Florida, USA

^a Kaunila sensor is based on Suunto MoveSense Technology (Suunto Oy, Vantaa, Finland).

Figure 1. Examples of the seven tasks that dogs performed during the experiment.

Top row: still tasks (Lying, Sitting, Standing). Bottom row: dynamic tasks (Walking, Sniffing, Trotting, Playing).

Table 2. Ethogram for annotation of dogs’ behaviors from video recordings.

Behavior	Description
Lying	The dog torso is touching the ground and hips are on the same level as the shoulders. The dog can change balance point without moving limbs.
Sitting	The dog has four extremities and the rump on the ground. The dog can change balance point from central to hip or vice versa.
Standing	The dog has the four extremities but not the torso touching the ground.
Walking	4-Beat gait where the dog moves its extremities at a slow speed, the legs are moved one by one in the order: left hind leg, left front leg, right hind leg and right front leg. The dog moves straight forward parallel to the wall or at a maximum 45 degrees angle from it.
Sniffing	The dog has its head below its backline and moves its muzzle close to the ground. The dog walks, stands or performs another slow movement, but its chest and bottom do not touch the ground. Taking food from the ground and eating it is included.
Trotting	2-Beat gait where the dog lifts and puts down extremities in diagonal pairs at a speed faster than walking.
Playing	Dog fast turning or spinning, accelerations, decelerations, galloping, pacing, trotting (including when changing direction), tugging, stalking, jumping, bowing and any other kind of movements faster than walking. Playing was only annotated in the Playing task.

Figure 2. Correlation of the activity scores obtained by different devices (panels A-C) and locations (panel D), given in counts per minute (cpm).

Comparison between minute-based activity scores collected simultaneously during the test (N = 3073 min) by ActiGraph GT9X Link placed on the back, ActiGraph GT9X Link placed on the neck, FitBark placed on the neck and Kaunila placed on the neck (Spearman's correlations, rS). The classified data points in the graphs are those fulfilling the time criteria of the behavior being performed ≥92% of the minute. A) Comparison between ActiGraph GT9X Link placed on the neck and FitBark activity scores. B) Comparison between ActiGraph GT9X Link placed on the neck and Kaunila activity scores. C) Comparison between FitBark and Kaunila activity scores. D) Comparison between ActiGraph GT9X Link placed on the neck and ActiGraph GT9X Link placed on the back activity scores.

Figure 3. Medians (with Q1 and Q3) of minute-based total activity score (in counts per minute; cpm) for the analyzed behaviors (in the horizontal axis), measured by the four devices.

A) ActiGraph GT9X Link (placed on the back); B) ActiGraph GT9X Link (placed on the neck); C) FitBark (placed on the neck) and D) Kaunila (placed on the neck). N refers to the number of dogs that performed the behavior as defined in the ethogram fulfilling the time criteria (≥92% of the minute) for at least one minute. Statistically significant difference (p < 0.05; Wilcoxon Signed Ranks tests) between behavior pairs is represented with a different letter; if no difference is found, the same letter is used in both behaviors.

Table 3. Accelerometer cutoffs and their accuracy for the different behaviors (lying, sitting, standing, walking, sniffing, trotting and playing) and devices (ActiGraph GT9X Link placed on the back and on the neck, FitBark and Kaunila). Cutoff = mean optimal cutoff calculated among the 10 training subsets; AUC (95% CI) = mean area under the curve with its 95% confidence interval among the 10 training subsets; Se = mean sensitivity among the 10 training subsets and Sp = mean specificity among the 10 training subsets.

Device	Behaviors	Cutoff	AUC (95% CI)	Se (%)	Sp (%)
ActiGraph GT9X Link (back)	Lying-sitting	0–82	0.878 (0.854–0.902)	64.51	85.35
	Standing	83–1082	0.689 (0.651–0.727)	45.29	80.27
	Static	0–1082	1 (1–1)	99.35	100
	Walking-sniffing	1083–4193	0.773 (0.743–0.802)	81.38	96.69
	Trotting	4194–9452	0.811 (0.784–0.838)	61.48	96.32
	Playing	≥ 9453	1 (1–1)	98.08	100
ActiGraph GT9X Link (neck)	Lying-sitting	0–74	0.871 (0.846–0.896)	30.32	95.38
	Standing	75–1378	0.681 (0.642–0.719)	76.34	65.21
	Static	0–1378	0.993 (0.989–0.997)	90.37	98.82
	Walking	1379–3138	0.699 (0.663–0.735)	61.35	88.76
	Sniffing	3139–4079	0.776 (0.747–0.806)	41.36	96.75
	Trotting	4080–8159	0.802 (0.772–0.832)	53.02	96.05
	Playing	≥ 8160	1 (1–1)	100	100
FitBark	Lying-sitting	0–0	0.864 (0.839–0.889)	34.56	91.49
	Standing	1–14	0.705 (0.667–0.743)	60.25	66.14
	Static	0–14	0.990 (0.986–0.994)	93.25	98.90
	Walking	15–27	0.653 (0.620–0.687)	69.51	93.44
	Sniffing	28–66	0.748 (0.718–0.778)	73.68	97.61
	Trotting	67–123	0.863 (0.840–0.886)	95.37	95.17
	Playing	≥ 124	0.994 (0.990–0.997)	69.37	99.67
Kaunila	Sitting	0–78	0.780 (0.750–0.811)	60.54	73.07
	Lying-standing	79–417	0.793 (0.762–0.823)	44.81	85.45
	Static	0–417	1 (0.999–1)	98.78	99.69
	Walking-sniffing	418–1309	0.75 (0.717–0.782)	98.20	98.69
	Playing	1310–1976	0.928 (0.909–0.947)	94.75	99.41
	Trotting	≥ 1977	0.998 (0.996–1)	95.19	99.55

Table 4. Confusion matrix showing the classification accuracy of ActiGraph GT9X Link placed on the back for the behaviors classified using activity scores. Classification accuracy is reported as the percentage (%) of the average amount of minutes fulfilling the time requirement and belonging to each category among the 10 testing subsets.

		Recorded behavior
		Lying-Sitting	Standing	Walking-Sniffing	Trotting	Playing
Classified behavior	Lying-sitting	64	52
	Standing	36	48
	Walking-sniffing	1		84	37
	Trotting			16	63	4
	Playing					96

Table 5. Confusion matrix showing the classification accuracy of ActiGraph GT9X Link placed on the neck for the behaviors classified using activity scores. Classification accuracy is reported as the percentage (%) of the average amount of minutes fulfilling the time requirement and belonging to each category among the 10 testing subsets.

		Recorded behavior
		Lying-sitting	Standing	Walking	Sniffing	Trotting	Playing
Classified behavior	Lying-sitting	32	18
	Standing	58	71	13
	Walking	9	11	58	38	16
	Sniffing		1	18	40	40
	Trotting	1		13	22	44
	Playing						100

Table 6. Confusion matrix showing the classification accuracy of FitBark placed on the neck for the behaviors classified using activity scores. Classification accuracy is reported as the percentage (%) of the average amount of minutes fulfilling the time requirement and belonging to each category among the 10 testing subsets.

		Recorded behavior
		Lying-Sitting	Standing	Walking	Sniffing	Trotting	Playing
Classified behavior	Lying-sitting	33	32
	Standing	60	62	6
	Walking	5	5	70	23
	Sniffing	2	2	20	77
	Trotting			4		92	22
	Playing					8	78

Table 7. Confusion matrix showing the classification accuracy of Kaunila placed on the neck for the behaviors classified using activity scores. Classification accuracy is reported as the percentage (%) of the average amount of minutes fulfilling the time requirement and belonging to each category among the 10 testing subsets.

		Recorded behavior
		Sitting	Lying-Standing	Walking-Sniffing	Playing	Trotting
Classified behavior	Sitting	59	57
	Lying-standing	40	41
	Walking-sniffing	1	2	98	2
	Playing			2	94	8
	Trotting				4	92