Very observant kid. She is currently studying for her PhD in biology. Gift to all of us nature nerds. Thanks Annie, much appreciate. And yes, by the time that teacher made that suggestion, I was already firmly committed to my desired career path!
Theodore Roosevelt is considered to have been a conservationist, but he was a tremendous persecutor of large predators, notably mountain lions. Thanks for your comment. And I understand your point of view. Even Aldo Leopold persecuted wolves although he had a change of heart.
And I should note that I know several accomplished and eloquent conservationists today who hunt mountain lions. Regarding Roosevelt, he was critical in establishing national parks, the national wildlife refuge system and so much more. I continue to wish for more like him, every day.
Great article…fascinating…….. I used to regularly find dead shrews,usually a foot above the water line near ponds after rainstorms,any clue why this happens? Just found a shrew in my back yard. My dogs have been barking at something and driving us crazy fo r the past week. Now we saw the shrew tonight and managed to get the dogs away from it with a hose. We have cats as well. Now what do we do with this animal. Its driving us nuts. Which reminds me we do feed the jay birds with nuts during the day.
So maybe that is why this creature has appeared. We live in Beaverton, Oregon. Can anyone help. So after having scouted a new suitable habitat, I installed a live trap, watched it constantly, and as soon as it snapped shut, I covered it with a cloth to reduce stress, and took it to the new location. I had te be quick, due to the fast metabolism. After opening the trap door, the shrew gingerly got out, looked back at me, shouted angrily something in shrewanese, and ran away.
I sure hope she got many offsprings. I caught a shrew today by the entry of a grocery store. I saw it running and it stopped sometimes and I picked it up..
I had gloves on. It nestled right down in my glove.. I put it in a little box with high sides, put the glove in the box and it hid under it. Took it to the humane society, talked with guy there, left it with them….
Am I crazy??? Maybe it died. It was a very cute little critter. Take nothing away from that. But the vole is a RODENT almost exclusively vegetarian whereas the shrew is a wild carnivore more related to a mole or a hedgehog. Compare their dentitions. I had looked up shrews to see why my barn cats ignored the trapped and killed shrew I offered them last night….. I get it now! Dear Matthew Miller …. My hero is Theodore Roosevelt!! I googled….
Plus someone else on the planet knew my Teddy story!!!!!!! Sure am glad your teacher directed you to the world of nature AND gave you an A. Thank you for the nice comment! It made my day. And always great to hear from another Roosevelt fan. Until yesterday I had never seen a shrew. We caught three running through our living room! We live in the country, and have had bats, mice and a squirrel come in but never a shrew! They looked like the ones at the top of your article.
Do they normally come into homes? Fascinating critters! Any thought? I have not heard of this but shrews do have variation in their pelt coloration. I will look into it more. Thanks for your question. I discovered six shrews in my compost bin during the turning process of producing usable material. On their exposure, they quickly scurried out of the bin through an entry hole at ground level.
One was caught, photographed and then released through their escape hole. The shrews had formed a chamber at ground level which I am assuming was a breeding chamber.
There is a meter of compost above ground level. The compost has a good supply of insects, worms, and woodlice, not sure about slugs or snails but in riddling the compost for use occasionally find empty snail shells. I really enjoyed reading and learning more about Shrews. What I wanted to know is if they do eat every 3 hours.
Do they have years they can live? Shrews have short life spans, from 1. Most do not reach old age. Life in the fast lane is tough! So tickled to read all your fascinating facts about shrews.
Roosevelt just went up another notch in my estimation and second your wish for another. Thanks for the lead to Dinets. Loved the article and learning about shrews! I agree with your professor, you are a fantastic nature writer! Thank you, that was both informative and entertaining. We caught a shrew in a mouse trap under the kitchen sink.
Reading your article makes me wiser! Last week I blamed my little chihuahua for chasing a skunk. Now I wonder if he had been chasing this shrew in our house or around it. I caught a northern short tailed shrew in my kitchen in Indianapolis today, and have enjoyed learning more about them.
Might the presence of the shrew explain the absence of the annual ant invasion this year? At any rate, I caught it in a live trap and released it in a nearby park. Hopefully I can find the hole it used to get in the house and seal it up.
If they bit a small dog that weighs only 3to 5pounds or a cat can it kill them? How would you get rid of them if you have them in your house? They do not possess enough venom to kill a small dog or cat. I would contact a pest control company if you have problems with them in your home. I spotted three young shrews in my garden all busy running around about 5 hours later I went out in the garden saw a bit of movement under a few leaves.
On closer inspection I found one eating another shrew and then spotted two more together dead, close together. Is this normal behaviour. I have a family of shrews in my kitchen and my three cats barely react to them. I think they live off the cat food. I had a baby one that wandered across the floor looking for water and I handled it before it ran off. I love to watch shrews. I have one that follows the same path every day at dusk.
I put peanuts out for a couple of chipmunks every evening so that when they start foraging in the morning, they will find something. Yesterday, I saw my shrew friend take a peanut into the dense plant growth along my walkway. I had no idea that they ate anything other than small mammals and insects. I will make sure that I put some seed and peanuts out for him also. Thanks for the info. Have just discovered a pile of 7 dead shrews by a burrow , very strange.
All in a neat little pile — any ideas? It is hard to tell. If the cat seems sick, you should see a veterinarian. In the past week I caught 3 shrews in the mouse traps set in my garage. Never thought they were around! I had peanut butter on the traps and they probably were attracted to that.
They were shrews because the nose was long and pointed, the tail was short, teeth were visible on the underside of the head and shorter legs.
They were the same grey color as the mice living around here. Years ago precisely 38 I had spotted what I thought was a velvety brownish grey mouse. It was late at night, and I was taking advantage of the quiet alone time that late night would afford me the time to focus on my creative sewing projects.
At the time, I was raising 2 little boys, ages 3 and 1 year. Late night was my escape into my own world of creative productivity. So on to the discovery of the shrew. I remember thinking that the following day would have to be my hunting day this mouse would be pardoned for this night at least I was not looking forward to sanitizing my dishwater, silverware, utensils ect..
Wiping everything down with disinfectant was a daunting, time consuming task that I was not looking forward to.
I really had better things to do with my time. On to the local hardware store to invest in some sort of contraption to catch these little critters that had so boldly taken up residence in my home.
As much as I wanted them gone, I had no desire to kill them. I figured he was going to stand his ground, so I would have to do the same. The guy at the hardware store said that it sounded more like a shrew and not a mouse. He then went on to tell me that I should be happy to share my home with this little critter, as they eat bugs and are not interested in any of the food in my pantry, except for maybe the cat and dog food.
And as far as pooping on my silverware, had I actually identified any droppings? Needless to say, I was eager to learn about this little critter that was feasting nightly on bugs and spiders, keeping my little boys safe from the possible poisonous bites of some of the common spiders found in the Midwest, which is where I live. To this day my 2 boys remember our shrew as more of a pet than a pest. My husband told me yesterday that we have a mouse, a very strange looking one. I laughed and told him to leave it alone and be grateful for him living in our old farmhouse, that chances are he the shrew would most likely keep our home mouse free for the winter.
I wonder what his name is…. I suspect in this case, the young are simply called baby shrews. Loved your shrew d observations, but disagree with wanting more politicians like Theodore Roosevelt. He was a merciless hunter of big game across the globe, and a war monger. As with so many public figures that we idolize without closer examination, he had some serious flaws as a humanitarian. Yes but could it be a snake or a mice that has took some peanuts that are not in the shell and put all of them in the living room in a perfect circle.
I just found a short tail shrew With no ears in my pool, unfortunately I was a little to late finding him, roughing him up did no good. And found out they are venomous, I had no clue. Thank you for taking the time to write this article! I missed my calling. But I study the flora and fauna found all over the world with a hungry intensity at the advanced age of nearly 63 now.
It was on the bank of the crystal clear lake surrounding the island, hunting. It actually allowing me to pick it up and never bit me. It was just beautiful. Thank you Matthew,! What an informative and interesting read! My cat has a dead shrew on the porch about every other day! Your info helped allay my fears that Jed was in danger.
Enjoyed it- thanks for putting in the Teddy Roosevelt bit. Glad I found you. Great read! Thank you!! I was waiting for warmer weather to arrive and finally it is here! Trade-offs may also occur between sensory systems: animals with a subterranean lifestyle such as the star-nosed mole have a highly developed mechanosensory modality with sensory specializations and expanded cortical areas at the expense of reduced vision with minute eyes and a small visual cortical region [ 21 ].
Similar trade-offs have been documented in the naked mole rat, which has been shown to be completely blind and possesses specialized sensory hairs along the body that might guide its movement within tunnels [ 22 , 23 ]. Small body size does not only directly impact on vibrotactile sensing, but it also results in unique selection pressures on the Etruscan shrew's hunting behaviour. Because of their small size and their large surface to volume ratio, Etruscan shrews have an extraordinarily high-energy turnover.
This presents an extreme challenge to all functions of the body, including respiration, oxygen transport, muscle parameters, but most importantly here the sensory and neural systems. Only because Etruscan shrews are highly efficient hunters, are they able to meet these extreme metabolic demands.
However, in case of food restriction and at low ambient temperature, they can reduce their body temperature and enter a torpid state to cut down their resting energy expenditure. Torpor is defined as a state of decreased physiological activity, usually characterized by a reduced body temperature and reduced metabolism. Under normothermic resting conditions, the specific oxygen consumption rate of S. A maximal heart rate of up to beats per minute exceeds all values reported for other endothermic animals [ 4 ].
This species has the highest mass-specific metabolic rate of all mammals [ 28 ] and thus there is an immense pressure to obtain prey. Shrews as small as S. Muscles play a major role in the capture and chewing of prey, but S.
Both structural and functional properties demonstrate that the Etruscan shrew's skeletal muscles are well adapted to fit the needs of this animal's extreme metabolism; they lack slow-twitch type I fibres and consist only of fast-twitch IID fibres. The enzymatic characteristics of these fibres make them optimally equipped for an almost purely oxidative metabolism [ 30 ].
With a brain mass of about 60 mg, the Etruscan shrew has the smallest mammalian brain known [ 31 ]. In such small brains, axons are typically densely packed, small in diameter and mostly unmyelinated. Unmyelinated axons have high capacitance per unit length and are energetically more expensive than myelinated axons [ 32 ].
In the tiny shrew, the estimated metabolic cost for generating an action potential for all white matter fibres averaged is an order of magnitude higher than in the macaque and 97 per cent of this cost is accounted for by the unmyelinated axons. In summary, surface to volume considerations imply that a homoeothermic body temperature is metabolically highly costly.
The musculature of Etruscan shrews is specialized for fast movement, and an increased body temperature might also offer massive advantages in terms of processing speed see below. There are more than species of shrews and they share common features, such as a small body size and prominent whiskers on a pointed snout. Shrews belong to the order Soricomorpha. Fossil evidence suggests that the earliest mammals were shrew-like in body size. Their brains were similarly small as those of extant shrews and possibly afforded similar behavioural capabilities [ 33 , 34 ].
Their habitat includes forest, shrub and grassland environments [ 35 ]. As for many other species in the genus Suncus , the Etruscan shrew is most likely solitary and territorial, except during the breeding season [ 36 , 37 ].
Being hunted by predator birds such as owls [ 38 ], shrews try to avoid moving uncovered in the open field, but rather seek shelter under piles of rock, pieces of bark or other organic material and in tunnels that they dig in loose soil.
Often they are found resting in old dry stone walls, where they also build nests for bringing up their young. Strikingly agile animals, shrews squeeze their body through tiny holes and they are able to enter and capture prey in slits as thin as 7 mm. Shrews are opportunist insectivores and all species consume a wide range of prey. Studies of the feeding habits of shrews and their prey availability demonstrate that small size brings benefits as well as costs [ 39 ].
The greatest advantages for small shrews are their lower absolute food requirements and the ability to subsist on small, numerous and accessible arthropods with high encounter rates, available in different seasons and low-productivity habitats. Major costs of small size are a reduction in food niche breadth and prey biomass resulting from restrictions on the type and size of prey eaten, and large territory requirements with a consequential increase in the energetic cost of foraging and territory maintenance.
Owing to their constant food requirement, shrews have polyphasic circadian activity patterns with frequent activity bouts distributed evenly over a period of 24 h [ 9 , 35 , 40 — 43 ]. This means that shrews have to be able to successfully hunt in twilight as well as in darkness. Vision can be furthermore limited in typical shrew habitats, such as dense brush vegetation or tunnels in stone walls or the soil [ 9 ] and indeed, sight only seems to play a minor role for navigation and prey capture [ 6 , 7 , 13 , 44 ].
While a few authors claimed that shrews make use of echolocation [ 45 — 48 ], others found no evidence for this ability [ 8 , 19 ]. A recent study proposed that shrew-like calls can yield echo scenes useful for habitat assessment at close range, beyond the range of the shrews' vibrissae. At the same time, it seems unlikely that they can make bat-like use of echolocation to search for prey [ 49 ].
In summary, we suggest that the secret life of Etruscan shrews in slits, where they hunt large and diverse prey, might predispose them to rely on proximal tactile cues. Crickets are found in abundance in the natural habitat of the Etruscan shrew and therefore are thought to be an important prey [ 2 ].
A cricket can measure up to 35 mm body of the Etruscan shrew measures between 35 and 50 mm and has very long antennae and prominent jumping legs figure 1 a. Crickets are fast moving prey and very capable of evading attacks. A variety of mechanoreceptors, different kinds of receptors and mechano sensory sensilla are found in and on the cricket body and appendages, just as in other insects e.
A cricket shows a range of behavioural responses to stimulation of its mechanoreceptors, extending from ignoring the stimulus to altering complex behavioural sequences such as avoidance manoeuvres, orientation and approach or fighting see [ 51 , 52 ].
Furthermore, the input from mechanoreceptors is known to inhibit ongoing behavioural activity, e. While the antennae are versatile head appendages with the ability to sense the environment up to twice its body length, cerci, the two caudal antenna-like appendages are mainly known to guard the rear of the insect [ 54 — 57 ].
Any defensive or escape behaviour guided by cercal mechanoreceptors depends on their stimulation [ 58 ]. Mechanisms of escape behaviour have been studied intensely [ 3 , 59 , 60 ]. Wind and touch stimuli have been used to study defensive kicking and escape responses.
When a digger wasp makes contact with the cricket, it first leads to a head stand sudden raising of the abdomen , followed by a stilt stand with the further raising and tilted posture, which is followed by a rapid kick with one hind leg casting the wasp several centimetres away. The kick is completed in ms after the touch and can also be followed by a second kick [ 52 , 61 ]. We observed that Etruscan shrews quickly retracted their snout after placing attacks on crickets, probably to avoid being kicked.
The escape response can be a turn, a jump or both and often is followed by running. Anjum et al. In these experiments, the spatio-temporal analysis of numerous attacks was combined with whisker removal and prey manipulation experiments. Etruscan shrews direct their attacks selectively to the cricket's thorax and manage to keep this precision regardless of the size of the prey figure 2 a,b. Although most attacks are directed straight ahead, there is a slight lateralization in the hunting behaviour towards rightward attacks.
Precision and speed of shrew attacks. Modified from Anjum et al. Modified from Munz et al. Dots and circles are the head positions of the shrew and cricket, respectively. Dots and circles are colour-coded for simultaneous head positions of the shrew and cricket.
Note the 29 ms lapse between the cricket's speed increase and the shrew's speed increase. The difference in time between the cricket and the shrew acceleration increase was 27 ms. Prey capture occurs very quickly, i. While first attacks were distributed relatively broadly over the cricket's body, subsequent attacks were directed more and more precisely to the thorax. Removal experiments showed that both macro- and microvibrissae are required for hunting [ 6 ].
Experiments with dummy prey objects showed that shrews attacked a plastic replica of a cricket but not other plastic objects of similar size. Altering the shape of crickets by gluing on additional body parts from donor animals revealed that the jumping legs but not the head are key features in prey recognition. Thus, tactile shape cues are both necessary and sufficient for evoking attacks.
Both the generalized effects of cricket shape manipulation experiments and characteristics of corrective manoeuvres indicate that shrew behaviour is guided by Gestalt-like prey descriptions [ 6 ]. We recently characterized Etruscan shrew whisking and tactile behaviour during prey capture [ 7 ]. To this end, we combined staged shrew—cricket encounters with whisker tagging and high-speed videography. Like other mammals, such as mice and rats, Etruscan shrews engage in rhythmic back and forth whisker movements, i.
The average power spectrum shows a very clear peak in the shrew whisking at approximately 14 Hz. This is a considerably higher whisking frequency than that of rats approx. Clearly, shrews employ periodic whisking during their hunting behaviour and the shrew whiskers are under active muscle control. Compared with rats, shrews had lower amplitude whisking approx. Interestingly, as in rats, retraction velocity was almost double protraction velocity.
Etruscan shrew whisking during hunting can be divided into phases: i immobile resting prior to hunting. Prior to hunting shrews often showed very little head or whisker movement. The beginning of the search phase was determined by an increase in the head velocity.
Concurrent with increased head motion the whisker set angle increased and whisker motion increased. During the search phase we often observed highly regular periodic whisking. The first whisker-to-cricket contact defined the transition from the search to the contact phase. This phase was kept very short by the shrew, as crickets tried to escape before the shrew was able to strike. Following contact, whisking amplitude decreased and there was a small increase in the whisker set angle.
Attack was defined by a sudden increase in head acceleration directed towards the cricket. This is a brief behavioural event with a sharp increase in head acceleration. The shrew's trunk dramatically bent during the strike and assumed the shape of a parrot beak.
As illustrated in figure 2 c — e , we found that shrews were able to react to cricket movements during the short duration of the attack.
In figure 2 c , we overlaid video images taken just before and at the end of an attack. The dots and circles show the head positions of the cricket and shrew, respectively, during the attack. The dots and circles are colour coded to show simultaneous shrew and cricket head positions note that the first four cricket head positions are nearly identical.
In this example, the shrew is initially moving upward in the video and the cricket is still. When the cricket suddenly jumps backward, the shrew reacts by adjusting its trajectory. We estimated the reaction time of the shrew by looking at the time delay between the cricket's sudden speed increase, corresponding to its attempted flight, and the shrew's increase in head speed as it adjusts its attack.
In this example, we found that it took the shrew only 29 ms to react to the cricket's escape attempt figure 2 d. On average, the shrew's increased head acceleration followed the cricket's sudden acceleration by 27 ms figure 2 e. It was previously reported that shrews react to underwater stimuli with a latency on the order of 20 ms, in good agreement with the values reported here [ 19 ].
Overall, the observations from high-speed videography strongly support the idea that shrews out-manoeuvre their very large prey by high-speed performance. Indeed, about 40 per cent of shrew attacks target stationary prey and the first strike often occurs prior to any evasive manoeuvre [ 6 ]. Both short reaction times and short attack intervals suggest that shrews identify and target their prey with a single touch.
The Etruscan shrew's prominent whisker fan has already been introduced in figure 1. Selective whisker removal experiments demonstrated a functional differentiation of shrew whiskers in prey capture [ 6 ].
Figure 3 a shows the left whiskerpad with the vibrissal follicles clearly visible. The whiskers on each side of an Etruscan shrew's snout are arranged in a grid made up of six rows A to F and several arcs.
Each row contains six to nine whiskers. In addition, there are three whiskers not contained in a row or an arc, labelled X, Y and Z. In total, there are more than hundred vibrissae extending like a fan from the snout of the Etruscan shrew.
In larger shrews, even higher numbers of vibrissae have been described [ 60 , 63 , 64 ]. Differences between shrew and rodent vibrissal follicles have been described [ 63 , 65 , 66 ]. Periphery of the Etruscan shrew vibrissal system.
In addition, there are three whiskers not contained in a row or an arc and labelled X, Y and Z. Scale bar applies to a and b. The trigeminal nerve is indicated as black arrows and optic nerve as blue arrows. R, rostral; C, caudal. Touch signals from the follicles are relayed to the brainstem via the trigeminal nerve. In the long-clawed shrew Sorex unguiculatus , which is about 10 times larger than the Etruscan shrew, each sinus hair follicle is innervated by 60— myelinated fibres [ 61 ].
The fibres from the sinus hair follicles join to form the maxillary branch of the trigeminal nerve. The thick trigeminal nerve compared with the much thinner other cranial nerves gives a stunning impression of the significance of touch information from the facial region for the Etruscan shrew. Figure 3 b shows the trigeminal nerve framed by black arrows and the optic nerve framed by blue arrows for comparison. The differences in macromorphology of the sensory cranial nerves are mirrored by the number of sensory fibres contained in those nerves.
In the northern short-tailed shrew Blarina brevicauda , there are about 15 fibres in the infraorbital part of the trigeminal nerve compared with less than fibres in the optic nerve [ 67 ]. More recently, differences in fibre distribution were reported for the similarly sized American water shrew Sorex palustris , which has about 30 axons in the trigeminal nerves, less than in the optic nerves and — in the auditory nerves [ 68 ].
The most extreme of the small mammals is probably the star-nosed mole Condylura cristata —its touch sensitive appendages are innervated by about myelinated nerve fibres [ 69 ]. The Etruscan shrew has the smallest brain of all mammals. As in other mammals, the cortex of the Etruscan shrew is a cytoarchitectonically heterogeneous sheet of tissue. The presence of distinct cortical areas is suggested by the fact that different staining methods Nissl, cytochrome oxidase activity, myelin indicate the same areal borders.
Sensory neocortical areas could be clearly identified by cytochrome oxidase and myelin staining in coronal and tangential brain sections. In total, there are about 10—15 cortical areas—a relatively large number given the small size of the Etruscan shrew cerebral cortex [ 71 , 72 ]. We compared volumes of cortical areas of the Etruscan shrew with data for the cerebral cortex of the rat, which is times larger than in the shrew.
We included all areas of the neocortex, as well as entorhinal and piriform cortex [ 72 , 73 ]. The most striking difference is that entorhinal cortex and piriform cortex comprise a much larger part of the cortical mantle in the Etruscan shrew approx.
The differences in relative cortical volumes are mirrored by findings in relative cortical area sizes [ 74 ] and neuron numbers [ 72 ]. In summary, the Etruscan shrew devotes a large cortical volume to somatosensation, whereas visual and auditory processing takes up only small fractions.
The superb tactile capacities are reflected in the anatomy of the shrew cortex. The neurophysiology of the Etruscan shrew is of interest both because of their small brain size and their remarkable behavioural capacities. Work on related northern American shrew species showed that these shrews have few sensory cortical areas, which include a large primary and secondary somatosensory cortical area and a primary visual and auditory cortex [ 15 ], a pattern in line with the numerous specializations of insectivores for somatosensation [ 21 ].
We investigated cortical organization in Etruscan shrews by electrophysiological mapping in combination with histological verification of recording sites [ 16 ]. We characterized cortical multi-unit responses to auditory, visual and somatosensory stimuli. At least two commenters got the animal right: They're shrews. And not just any shrews — that fuzzy conga is a mother shrew leading her babies in a train, known as a caravan, according to Cynthia Alvarado, a clinical veterinarian at the Jackson Laboratory in Bar Harbor, Maine.
Here's how the caravan works: The mother shrew heads the line, and each preceding baby shrew bites down on the base of the tail belonging to the shrew in front of it. Then, with Mom in the lead, the shrews can travel together in a fairly ordered procession. Shrews typically form these caravans when their nest is disturbed and the mother decides to evacuate her young to safety, according to the Mammal Society , a charity in the United Kingdom that advocates science-led mammal conservation.
Caravans may also be used to encourage shrew pups to explore their surroundings, the society noted.
0コメント