Episode 38 of the podcast is up! Listen on Podbean, or wherever you get your podcasts. I continue my review of Honeybee Democracy by Thomas Seeley. This episode covers information on the intrepid little explorers known as scout bees!
Homestead Updates
Brood X cicadas. These cicadas emerge every 17 years, and they will be emerging in Spring 2021 in 15 states. Ohio is one of these states. Eek! Sometimes called ‘locusts’, there are 3 species that will be merging this year after a long dormancy: magicicada septendecim, magicicada cassini, magicicada septendecula. It looks like I am safe as my county is not in the list of known areas for this brood. Those OH counties are Defiance, Franklin, Greene, Hamilton, Logan, Montgomery. I found the state and county info on where this brood is expected to emerge on this website. These bugs will emerge between May and June, when the temp is above 64F, and usually after a warm rain. Brace yourselves!
Europa update: the pin in her jaw came out, exactly 3 weeks after the surgery. This is a little earlier than usual (recommendation is 4-6 weeks, depending on healing process) but the vet felt that it was contributing to the bowing of the jaw, and he hopes that removing it a little early will allow the bone to heal in a more natural position. It already looks so much better! I’m so pleased with her progress, and so very grateful for my vet and all the staff there. They take such good care of my pets!
Rooster news: Pepperjack doesn’t charge me very much anymore. Some things definitely trigger his bad behaviour, though. For instance, if I turn my back on him and walk quickly away, he will run me down and try to peck me! But generally speaking he is a lot less defensive and balshy. Sometimes he’ll peck my boot or knee but it doesn’t have any heat behind it. I’ve also learned that I can pet his fluffy butt! He hates to be touched on his front or back but I can reach into all that butt fluff and pet him with no reaction. Rather odd!
Squeak update: no additional signs of vent gleet so far. I haven’t noticed any discharge, her vent is a healthy pink colour, and I’ve seen no evidence of diarrhea in the coop or run. I’m still giving yoghurt every now and then, and being especially careful to keep their water sparkling clean. As for the lice, the diatomaceous earth is helping but hasn’t fully resolved the issue. I’m going to use Frontline next time I have a pack open for the dogs. It worked so well on Agatha that I think it will do the trick for Squeak. I didn’t use it on her before because it’s not egg safe and she was still laying but now I think it’s worth it. She hasn’t produced an egg in quite some time, and her eggs have always been a bit weird, so I’m okay with disposing of any she might produce in the future.
I wanted to mention my experience with Grubblies. They’re dried soldier fly larvae, and I have mentioned them before since I was very pleased to find a US based company (most mealworms come from China). But I have yet to mention that I started buying their chicken feed. The downside is that it’s more expensive than what I pay at TSC for Purina or similar brand:Grubbly feed is $42.99 for 30lbs but you save if you set up auto-deliver; $38.69/30lbs. I also have found that this isn’t enough per month to feed my flock of 11 (10 hens, 1 rooster). BUT the positive is that, even when mixing it with another feed, I have noticed an improvement in egg shell thickness and overall quality. Plus, the girls LOVE IT. If I could justify paying for the larger size ($71.99/60lbs), I would do so but, right now, I am happy using it to supplement their regular feed. I do think it’s high quality based on the change I’ve seen in their eggs. I also love that it comes in a sturdy, paper-based bag instead of plastic, and that they make the delivery process so easy. Grubblies seems like a genuinely good company and I’m happy to support them with my business. Has anyone else tried the feed? I’d be interested to hear your opinion. In the meantime, you can learn more about Grubbly products on their website.
Hive Updates
No real news as we’re still in the heart of winter here in Ohio.
I did pop out with the stethoscope again; all seem to be alive but some clearly weaker than others, and I’m still quite worried about queen Macha’s colony
Thinking about what I want to achieve with my bees this year; simplifying some things, really focusing on good health and quality over quantity; working more with my mentees; trying new mite treatments and tracking the results; setting up swarm traps, etc.
Bee book recommendation: Queenspotting book by Hillary Kearney. Such a wonderful book! It’s not just a queenspotting guide but also a fantastic overview of the hive, the bees and their functions, and so much information on the queen. The author’s clear love for honeybees really shines from every page, and the photography is wonderful. Gazing at those double pages of bees, looking for the queen, made me feel like I was visiting a hive. A bit of Spring and Summer is in these pages! Highly recommend you grab a copy. Available at all major book stores, Amazon, and on her website.
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Chapter 4: Scout Bee’s Debate
The experience of democracy is like the experience of life itself -
Always changing, infinite in its variety, sometimes turbulent
And all the more valuable for having been tested by adversity.
-Jimmy Carter, Address to the Parliament of India, 1978
A honeybee swarm uses direct democracy: the individuals of the community participate directly in the decision making process, as opposed to working through a representative
Seeley likens this process to that of a New England town meeting where registered voters congregate to discuss issues and vote on them
The difference between honeybee swarms and town meetings is that the swarm has a common interest and build a consensus to make a decision, whereas those at a town meeting have conflicting opinions and reach a decision by a majority voting rule
A town meeting is designed so that the participants gain an overview of all issues raised, whereas a scout bee can only observe and interact with the bees closest to her in the cluster (she doesn’t have access to the information of all the bees combined)
What is similar between swarms and town meetings is that a decision is based on many contributions and observations, all equally weighted
“In other words the control of the group’s actions is distributed among many of its members rather than concentrated in a few leaders.” Pg.74
All information is offered from so many participants that knowledge gained is more numerous and offers a greater insight than that contributed by just a few
To reach a decision, both swarms and town meetings use an open competition process for the proposed options; a proposal can be accepted or rejected, and an accepted proposal can then gain more popularity until enough community support makes it the top choice
In a swarm, scout bees might all enthusiastically dance for different locations at the same time; competition can be fierce! But it is always friendly.
Ultimately, the scout bees all agree on what makes an ideal nest site, and are united in their goal of choosing the best one
“One valuable lesson that we can learn from the bees is that holding an open and fair competition of ideas is a smart solution to the problem of making a decision based on a pool of information dispersed across a group of individuals.” Pg.75
Lindauer’s Swarms
As mentioned in chapter 1, Martin Lindauer discovered the democratic process of honeybee swarms in 1951 and 1952 when he was able to study the swarms coming from the bee colonies kept in the garden of the Zoologist Institute at the University of Munich
Lindauer studied 17 swarms across the months of May, June, and July
Initially, he sought to determine whether the bees dancing on the swarm were nest-site scouts but he also wanted to discover exactly how a swarm finds and chooses a new home
He started by watching a swarm cluster for hours at a time, and then marked with paint those bees that danced on its surface
Incredibly, Karl von Frisch had created a marking scheme that allows one to label bees from 1-599 with just 5 paint colours! Lindauer used this system
At first, all seemed to be going well as just a few bees danced at the start of his observation so he was able to make detailed notes for each dance and dancer; her colour ID, the time of her dance, and the location advertised
Over time, however, more than a dozen bees would be dancing enthusiastically and simultaneously on the swarm, and it was almost impossible to keep track of each dancer
In response, Lindauer pared down his notations to the time he saw each dancer and the location she advertised
This was time consuming and tiring work but, thankfully, it revealed much to him, and we learned in chapter 1 how Lindauer discovered that the site advertised unanimously by the bees was the ultimate destination when the swarm flew off from their resting place
Seeley goes on to discuss some of the individual swarms Lindauer studied
He starts with the Eck Swarm; this swarm left its parent hive at 1.35pm on June 26th, 1951, settled on a bush, and hung there for almost 4 full days while the scout bees looked for a new home
On the first day, Lindauer noted and labeled 2 dancers between 1.35pm and 3pm; one reported a site approximately 1500 meters to the North, and the other a site 300 meters Southeast
By 3pm, rain clouds moved overhead and the temperature began to fall so the scout bees ceased their investigation for the day, returning to the cluster
On the 2nd day, Lindauer labeled 11 new dancers between noon and 5pm; 3 advertised the Northern site of the day before, 2 advertised the Southeast location, and 6 dancers indicated 6 different sites in various locations
Clearly, no agreement had been reached during this second day
On the 3rd day, the weather was mostly rainy and Lindauer noted just 2 new dancers, both arriving late morning; one advertised the northern site, and the other a new site 400 meters Southwest
On the 4th day, the weather was much improved (warm with clear skies!) and the scout bees quickly went to work with 20 new sites found and advertised
The previously popular site to the North did not gain additional dancers
Between 9.30am and 4pm, 9 bees advertised a site 1500 meters to the West but interest seemed to wane and from 4-5pm no new dancers advertised this location
The site located 300 meters Southeast held the bees’ interest for the full day with new dancers acquired each hour
Between 4 and 5pm, the recruitment of scouts for this location overwhelmed all others with 61 new dancers advertising, and only 2 new dancers for alternate locations
By the following morning, support for the Southeast site remained the same with 83 of 85 bees advertising for it
At 9.40am on June 30th, the swarm flew 300 meters to the SE site to take up residence (the nest cavity was in the wall of a bombed building)
This pattern of dancers advertising different locations until, over time, new dancers focus on one of the sites almost exclusively, and ultimately the swarm departs towards that location was repeated by all the swarms Lindauer studied with just a few exceptions
Occasionally, this process was not quite as smooth or linear
For example, sometimes scout bees would find 2 sites of apparently equal desirability as each would recruit new dancers at a steady rate, making it hard for the dancing bees to reach an agreement
This occurred with Lindauer’s Propylaen swarm in his study
The Propylaen swarm left the parent hive at 2.14pm on June 11th, 1952
That afternoon, scouts reported 11 sites, one of which attracted a large number of dancers; 15 bees danced for a site 900 meters Northeast, and only 14 bee danced for the other 10 sites
This made it seem to Lindauer that an agreement had been reached quickly (in less than 3 hours)
On the morning of the 2nd day, however, a site 1400 meters to the Southwest attracted a strong group of dancers
Throughout the day, the number of dancers for the NE and SW sites were near identical; the dance off raged on!
On the 3rd day, June 13th, a victor began to emerge: the NE location
From 12-2pm, the NE site recruited 25 new dancers vs 9
for the SW site
Between 2-4pm, the NE site had 41 dancers vs 7 for SW
From 4-5pm, the NE site had 34 new dancers and the SW site had no new dancers
By the end of the third day, an agreement had clearly been reached but it was now too late in the day for the swarm to leave, and the following day was cold and rainy (not good flying weather) so it was not until June 15th, 4 full days after leaving the parent hive, that the bees flew to the NE site to take up residence
Seeley adds here that, interestingly, swarms rarely take flight after 5pm, and posits that this might be because the lower light makes it harder to find the queen should she fall behind or stop for a rest (which is not abnormal)
We see then that, sometimes, the process of agreement can take a few twists and turns!
Lindauer even encountered a swarm that failed to reach an agreement; the Balcony swarm
This swarm left its parent hive on June 22nd, 1952, and its scout bees got into a balanced competition with one group dancing for a site 600 meters Northwest, and one dancing for a site 800 meters Southwest
Over 4 hours (from 12-4pm) neither group took the lead
Amazingly, at 4.10pm, the swarm took flight and basically divided itself; half the bees flew NW and half SW!
Neither group continued to their destination, however, and eventually the groups reunited in the air near where they had rested as a cluster
Over the next 30 minutes, a tug of war began with the NW group flying 100 meters away before returning, and the SW group flying 150 meters before returning
Eventually, the bees returned to a single cluster on the balcony where they had started
Sadly, further observation made it clear that during the kerfuffle the swarm had somehow lost their queen
As a result, over the next few hours, the bees of the swarm slowly began to drift away, a few at a time, back toward the parent hive
The sad fate of this swarm demonstrates that the decision-making process is not infallible
Occasionally, a swarm will come to a split decision such as this, and further debate is ultimately needed for success
Of the 17 swarms that Lindauer studied, just 2 produced split decisions but only the Balcony swarm failed to reach an agreement, and this appeared to be due to the loss of their queen, so it seems that total failure to reach a consensus is rare and due to mitigating factors (in this case: queen loss)
Perhaps the most interesting observation of the Balcony swarm is the fact that the swarm flew before a consensus was reached, which indicates that the strong indication of dancer consensus that we can see as outside observers is not what the bees monitor to know when to switch from making a decision to implementing a decision
Seeley tells us that how bees actually make this switch will be revealed in chapter 7 (Initiating the Move to a New Home)
My Swarms
Seeley notes that Martin Lindauer was a true trailblazer in his field and, despite his great abilities and insights, he was hampered by his time, particularly in the lack of sophisticated equipment
Lindauer worked using little more than a notebook, watch, and paint, and this limited him through no fault of his own to recording only new dancers on his swarm
Ideally, he would have recorded new and old dancers at each stage of the decision-making process, to give a clearer picture of the dynamics in the dancing for various locations
This would have allowed him to ascertain the total number of dancers for each location, not just the new dancers/recruits
Lindauer’s work shows that the winning site was the one advertised by the greatest number of new dancers but it did not indicate whether this was the greater number of dancers as a whole.
Can we assume that the winning site has won over all the dancers, both old and new?
Lindauer suggested that this is the case; dancers for less popular sites ultimately stopped trying to recruit others but he did not indicate whether this was through ceasing to dance period or switching to dancing for the popular site
Seeley has many questions about a dancer’s role in the process: is the total amount of dancing related to the quality of the site? If a dancer stops dancing, how does she decide to do so? Does she stop of her own accord or only if other dancers are more vigorous and/or popular?
Lindauer’s study does not answer these questions, and so Seeley decided to tackle them!
In 1996, Seeley began this process, almost 20 years after he had finished his PhD thesis research on the nest-site preference of honeybees, and how they estimate cavity volume
Was there a reason he waited so long to build on Lindauer’s work despite his keen interest? Yup! In the 70s, when he was working on his thesis, he could not get access to the kind of recording equipment he anticipated needing; at the time, the video camera, recorder, and monitor were all separate pieces of equipment, and cost thousands of dollars
Seeley was keenly aware of the limiting factor of the equipment available as well as the great expense, and so he focused on more accessible work that was still related to how social animals make collective decisions
Specifically, he looked at how a honeybee colony deploys foragers amongst their many foraging options
“This is a different sort of collective choice, for whereas a homeless swarm makes a “consensus decision” about which single option (candidate nest site) it will choose, a foraging colony makes a “combined decision” about how to allocate its foragers among multiple options.” Pg.86
For nearly 15 years, Seeley studied how honeybees work as a united whole to forage, and how they wisely distribute themselves among available food sources
In 1995, this work was summarized in his book, ‘The Wisdom of the Hive’, and then Seeley moved on to his next focus: the collective decision making of honeybee swarms
He knew where he needed to begin: he would obtain a complete record of the scout bees’ dances throughout every stage of the swarm’s decision making process
Unlike Lindauer 40 years before, or himself 20 years ago, Seeley now had access to sophisticated video recording and slow-motion playback equipment
Seeley had also learned how to label thousands of bees for individual identification using plastic colour-number tags glued to the thorax, and paint marks dotted on the abdomen; this should allow tracking of each individual’s dancing from start to finish
Just labeling the bees alone would be exhaustive work, and then there is the equipment to maintain and recordings to be carefully combed through
What is a professor to do? Recruit an undergraduate!
“It was my immense good fortune to be joined in this endeavor by Susannah Buhrman, an extremely bright and indefatigable undergraduate student at Cornell.” Pg.87
My note: a good undergraduate is worth their weight in gold!
Seeley and Buhrman worked together throughout the summer of 1997
They studied 3 swarms and obtained a complete record of all the dances performed for each
Swarm 1:
Observation began at 10am, June 19th
Scouts reported discoveries between 1 and 3pm, with 7 sites reported by the end of the day; no clear front runner
On the 2nd day, 4 additional sites were advertised and 3 sites had received the most support: G (2,200 meters Southeast), H (2,600m East), and I (4,200m South)
Between 12 and 2pm, site I took the lead with 23 of 25 dancers, and it remained in the lead throughout the afternoon, although 2 additional sites gained support (L and M)
The next morning, there was a clear consensus: site I was the winner!
At 9.10am, the swarm flew South
The debate witnessed at swarm 1 is similar to what Lindauer saw with his Eck swarm; during the first half of the decision making process, numerous sites were reported; in the second half of the debate, the dancers quickly became focused on one site
Seeley’s study noted the total number of dancers, not just the newly recruited, and so we can be confident that the swarm’s decision was due to a real consensus among all the dancing bees
Swarm 3:
This swarm was notable as there was strong competition between 2 groups of dancers
The swarm was set up at 2.30pm on July 19th
The next day, between 11am and 1pm, 6 sites were announced (A-F), with site A (2,200 meters East) developing a strong lead of 8 dancing bees
Over the next 4 hours, 3 more sites (G,H,I) were reported, and some 4 sites were leading (A, B, D, G)
Site A was starting to lose its initial lead as sites B (900m South) and site G (1400m Southwest) gained more support
Between 3 and 5pm, 4 bees danced for A, whereas 17 bees danced for B, and 10 for G
Over the next 2 hours, bees danced for 7 sites (including 2 new ones: J and K), though only B and G had the support of multiple bees
Seeley and Buhrman made a bet at this point as to which site (B or G) would be the ultimate winner, with the loser treating the winner to a triple scoop of ice cream at the newly opened Ben & Jerry’s in Ithaca! Seeley chose site B, Buhrman site G
The next day, between 7 and 9am, both sites were advertised by 12 dancing bees
From 9am to 11am, there were now 32 dancers for G and 17 for B
Between 11 and 11.45am (when it began to rain), G was a strong lead with 20 dancers versus 4 for B
The rain continued for the rest of that day and through the night so it wasn’t until 9am of the following day that the dance off continued, and now there was unanimous support for site G with 73 of 73 dancers!
A little before noon, the swarm flew off to the Southwest and, not long after, Seeley and Buhrman went to Ben & Jerry’s for some well deserved ice cream (with Seeley paying!)
“It was a great pleasure to watch the dance competition among scout bees, but it was an even deeper pleasure to analyze the diagrams. . . that we prepared many weeks later, after we had extracted all the information we needed from our 48 hours of video recordings.” Pg.91 A very biologist thing to say!
The videos illuminated that the bee’s debate tends to start with a slow information accumulation phase where many options are brought to the table to be considered
Of the 3 swarms observed, the total number of sites considered were 13, 5, and 11 respectively
Sites were in various directions and distances with scouts searching some 70 square-kilometers (30 square-miles)
Most sites were introduced during the first stage of debate but some introduced later (as seen with sites L and M of swarm 1)
Scout bee debate ends with all or nearly all bees dancing for one site: consensus
This raises the question: how are bees recruited to dance for one site while others fall from favour? Seeley says this will be discussed in detail in Chapter 6
The decision making process is democratic in nature, involving dozens or even hundreds of individuals
73, 47, and 149 bees danced of the 3 swarms studied
These swarms were smaller than those in nature with 3252, 2357, and 3649 bees respectively, compared to the 6-14 thousand of natural swarms
The percentage of dancers in the study group comes to 2.8%, which is close to the 5.4% reported by David Gilley in his study of natural swarms (more on this soon)
If 3-5% of bees participate in the dance debate, this works out to be about 300-500 bees in a typical swarm of 10,000 bees!
Intrepid Explorers
Consider what we know about the worker bee lifespan: worker bees have short lives, 3-5 weeks during the warm months of the year, and swarming occurs in late Spring and early summer usually, so we can surmise that many generations of worker bees come and go before scout bees are needed
So what causes some worker bees to take on the important role of a scout when the need arises? Who are these intrepid explorers?
Scout bees are foragers who switch from finding food to finding potential nest sites; they go from working in the sunlight, to searching out dark cavities
The first evidence that workers switch to scouting came from an experiment by Martin Lindauer in 1954
In May of that year, he set up a colony in an area of Munich that was largely flat, offering few trees or houses that might harbor potential nest sites
The area did have bountiful forage, however, and soon the bees were packing their hive with brood, pollen, and honey, and Lindauer predicted they would swarm, which they did on May 27th
On May 17th, 10 days before, Lindauer had set up a sugar feeder on a table some 250 meters/820 feet from the hive, and soon had more than 100 bees visiting the feeder to drink down the syrup
He labeled each of the foragers with paint for individual identification
On May 22nd, he placed 2 artificial nest sites (a straw skep and a wooden hive) beside the feeding area
Over the next few days, Lindauer noticed that the foraging bees’ behaviour was changing; they were less interested in the sugar syrup, and seemed to eat it more tentatively compared to their previous eagerness
On May 25th, he noticed that his labeled bees might take a sip or 2 of syrup but would then fly up and around the area
He realised that they were showing interest in the knothole of a nearby oak tree, as well as his 2 artificial nests
That afternoon, 6 of his labeled foragers conducted 15 inspections of the skep and 8 of the wooden hive
Clearly, some of his foragers were now scouts!
Second evidence of this change from forager to scout came from a study by Dave Gilley
Dave Gilley, at the time, was a gifted undergraduate student who had joined Seeley’s lab
He needed a senior thesis topic and wanted to work with bees so he asked Seeley for ideas
Seeley suggested he look into the mystery of which bees become scouts and Gilley happily agreed
Lindauer had shown that some scouts were previously foragers; Gilley wanted to see if all or most scouts were previously foragers
Foragers are the oldest bees in a hive, and so scout bees should be older as well
To test this, in early May 1996, Gilley set up 5 small colonies of bees, and would add 100 freshly-emerged (0 day old) bees to each colony every 3 days (from May 5th to July 22nd)
All of the bees from each age group were given a particular paint colour so they could be tracked within the colony
In June and July, all 5 colonies swarmed
Once a swarm had settled in its cluster, Gilley would watch and wait for dancers; each time he saw such, he could identify her age by her paint-dot colour, and would then mark her again so that she would not be recounted
Once he had 50 or so scouts of known age, he collected the swarm and euthanized it so he could count how many were from each age group
His results showed that nest site scouts included many more older bees than would be expected if known-age scouts had been selected at random from a pot of known-age foragers
Scouts, therefore, come largely from the colony’s experienced foragers
We can see why experienced foragers would make good scouts as they’re used to flying potentially long distances from the hive to find food, and then successfully navigating their way back
These results also show that many foragers do not become scout bees. Why not?
Seeley points out that we now know that genetics play a role, with certain genes predisposing a bee to serve as a scout
This was demonstrated by two behavioral geneticists, Gene E. Robinson and Robert E. Page Jr., now professors at the University of Illinois and Arizona State University respectively
They set up 3 colonies, each with a queen who had been inseminated with semen from 3 unrelated drones (A, B, and C)
These 3 drones each carried distinct genetic markers, allowing their offspring to be easily identified by the investigators
Robinson and Page created artificial swarms from their colonies, set them up outside, and collected 40 scouts (dancers) and 40 non-scouts (non-dancers) from each
A paternity analysis was performed on these sampled bees and the results analyzed to determine if offspring of certain drones were more likely to be scouts
They found that the offspring of the 3 drones differed dramatically in the likelihood of becoming scouts, with one drone fathering 60% of all scout bees, even though he fathered just 20% of the total worker bees. Did his genes make his daughters scouts?
Even knowing that some worker bees have genes that foster exploratory behaviour, how do the bees know when it is the right time to start scouting?
Amazingly, a full stomach might be the key!
Seeley observed when setting up artificial swarms that, if the bees were not kept sufficiently well-fed, no scout bees appeared
As a reminder: creating an artificial swarm involves removing the queen and then shaking some several thousand bees into an empty swarm cage (placing the queen carefully in with them); a shoebox sized wooden or plastic box with screened sides for ventilation then feeding the bees heavily by brushing sugar syrup on the screens
If the worker bees are well fed like this then, in a few days, scout bees will spring into action
Thus, it appears that a forager with a full stomach for several days will transform herself into a scout
Lindauer observed something similar in his May 1954 studied mentioned earlier
When he set out his syrup feeder on May 17th, there was little natural forage available and so the bees danced enthusiastically for the feeder location, and would return to the hive loaded up on the sugar syrup
After May 22nd, however, the horse chestnut trees were in full bloom, and the colony’s comb was soon packed with honey
When foragers returned to the hive with full stomachs they had increasing difficulty finding hive bees to pass their sweet load to
With their comb laden with brood and food, the returning foragers are forced to rest with bulging stomachs of nectar (or syrup)
“This forced inactivity may stimulate a few foragers, those who are constitutionally inclined to explore, to turn to nest-site scouting.” Pg.98
Seeley notes that he finds it “extremely suggestive” that not long after Lindauer observed previously active foragers sitting idly or ‘bearding’ at the hive entrance, he noticed some of his marked foragers explore his offered nest sites
And that’s it for this chapter!
Join me in two weeks for Chapter 5: Agreement on Best Site.
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In the meantime, I'm taking advantage of any sunny days we get, no matter how cold, by loading the pups in the car and heading outside for a good, brisk walk!
