Thread by @IrelandsEnviro

#IrishCaveBones 1/n May the (Day) 4(th) be with you all! (sorry couldn't help StarWars ref with the day that's in it!). Now, I'm (@RuthFCarden) going to grab mug of tea & I suggest you grab your choice beverage, I don't know how long this will be - a lot of info & Qs to ask.

@RuthFCarden 2/n Now, let's get into tonight's thread, all about Ireland's animals - origins, what does the word native mean and to whom and how we use it, what we mean by naturalised species, (re)introductions and so on, but we need to start back in time first of all...

3/n...back to Irish caves and the secrets contained in them - #IrishCaveBones - I need to set the scene first before moving on. An important project was completed in the mid 1990s by the late Prof. Peter Woodman - called the Irish Quaternary Fauna Project. Published in 1997 in

4/n the scientific journal Quaternary Science Reviews. Peter got funding from The Heritage Council to radiocarbon date 100 animal bones from different species and mainly from cave sites across the island, & some archaeological surface sites.

5/n This was phenomenal undertaking at the time and was all to investigate when animal species were in Ireland during the past 50,000 years - the limitations of radiocarbon dating using the method. 100 radiocarbon dates....100!!! Each date (today) costs Euro345. This was the

6/n first time significant funding had been given to understanding Ireland's animals in the past, the important 'when' question. Because, if we know when, AND we know what species, we can gain info on what type of climate there was, as certain animals only inhabit certain

7/n conditions and also only inhabit certain landscapes with certain plant and tree species. We can gain other inferences of diet and habitat relationships through analysis of stable isotopes too (more on this later).

8/n 100 'whens' opened up doors into our thinking and understanding of when certain species of animals occurred in Ireland during the past 50,000 years. It led us to think about modern day conservation plans for certain species that were here before or after the last Ice Age.

9/n Not since the original cave excavations by Ussher, Adams, Plunket and others, when they could only assume certain species were 'old' or appeared in Ireland at certain points - but radiocarbon dating provides the actual answers, and dating is the spine from which everything

10/n we think about Ireland's animals hang off. It's the one piece of data that is key to unlocking EVERYTHING else, all the other analysis we can do hinges on placing that animal in time in the past - the 'when' is keystone to our palaeo-ecosystem time puzzles.

11/n With Peter's published 100 dates for all Irish species from their cave bone samples were investigated a bit further, certain animals in time didn't make total sense. Given usually cold adapted species occur during cold times (we know from geology and ice core data) in tundra

12/n It would be some years before Peter came back to these data as other new data came to light (some from our origins of Irish red deer work, where previously identified red deer bone samples from Peter's 100 dates, were reindeer proved by ancient DNA extractions). These were

13/n radiocarbon dated again BUT, the 'new' dates did not match the 'original Peter 100 date'. 🤔Peter and I had lots of discussions about where certain species were on the timeline and the ice core climatic data, and things weren't making sense. Then coupled with the new dating

14/n we discovered that radiocarbon dating methods were now (from the early-mid 2000s) using an ultra-filtration step that eliminated any contaminates in the cave bone samples (samples = c.1g in weight). This filtration method produced accurate radiocarbon dates. Even though

15/n Peter's original 100 dates formed a huge important contribution to the palaeo-research of Ireland's animals in the 1990s+ , unfortunately, these were inaccurate due to the presence of contaminants in the bone samples (pre-ultra filtration step). 😭

16/n I can't stress enough how important radiocarbon dating animal bones from our prehistory is - not only do our palaeo-research and climatic models rely on these dates, but also within zoological studies, certain species have been called 'native' (got here by themselves without

17/n any interference from humans), based on their dated remains. Molecular ecological studies and research, where extractions of DNA is taken from animal tissues and seqeunced, and compared to other populations in same island or across different countries. They use a form of

18/n modelling using molecular clocks, to trace back in time using the DNA data to when that species occurred in a geographical area. They use radiocarbon dated fossils/old bones to calibrate these clocks .... so if the radiocarbon date is wrong, their clocks are wrong & their

19/n interpretations of the species' ecology and natural history is wrong. Also all our determined 'native' species relied on the original identifications of the cave bones and their intrepretations since - remember the misidenifications of the cave bones from earlier thread?

20/n remember if the radiocarbon date is wrong or inaccurate -the knock on effects are huge. They may start small, but over time and effort by different parties, the impacts are significant - think the Butterfly Effect! This is why dating is cruical to #IrishCaveBones research!

21/n so, Peter & I set about finding the original bone samples left over from the previous dating of the 100 in the Museum stores. We found most of them and in collaboration with Tom Higham, we redated 25 cave bone samples from three different caves - Castlepook cave, Foley cave,

22/n and Shandon cave. These new dates, gave us the accruate timeline of Ireland's animals for the past 50,000 years. Some of the new dates moved between 2,000 to 12,000 years older, with only two samples moving c.2,000 years younger. Now we have the correct timeline and can

23/n infer so much from the species through time. Let's go with each species, that we have data, obviously we need to date so many more (see Day 7 on Sunday for more info on this) from different caves, but for now we have a good snapshot of life on our island. Let's get into it!

24/n Intermission - if people get the adult cartoon reference, bonus points to ye.
I could not help arrange these old museum labels found amongst cave bones this way 🤣😅 I like to have fun at work!

25/n So we wipe the radiocarbon date slate clean. Forget those 100 dates previously published. We use data published in 2020 for our timeline. Unfortunately, Peter passed away before we published the new dates using the same bone samples he used the first time in his 100 study.

26/n Irish Mountain hare:
Old date 28,240yrs
New date >49,000yrs.
That's a huge leap for our hare back in time, a native species if ever there was one. We have had hare here for a long time before we became a island and after an island once again, and into today. It's adapted

27/n to tundra, Arctic cold conditions. In some upland mountainous parts of Co. Kerry, the hare still turns partially/wholly white in winter. A throw back to when Ireland was covered in snow for all winter and camo against predators (eagles etc). Ancient DNA studies are still

28/n outstanding for our hare here and long over due at this stage comparing ancient populations with modern day populations. But certainly we have more hare bones for dating, & we will be extracting stable isotopes from them too to look at diets, palaeo-foodwebs etc.

29/n Arctic fox:
Now we will be doing further work on this fox bones and comparing to red fox in terms of anatomy, bone measurements, ancient DNA, isotopes etc. Because from what I've examined and assessed in terms of the fox bones in the Museum collections, they

30/n aren't very like Arctic fox at all, and more morphologically similar to red fox. So for now, we will call this fox species.
old date: (a) 19,950yrs; (b) 29,980yrs
new date: (a) 31,030yrs; (b) 29,990yrs
(a)-(a) - another leap back in time
(b)-(b) - v.small step back in time

31/n: Now if it isn't Arctic fox, and is Red fox, then red fox might be a generally all-rounder in terms of habitats and cold/warm temperatures in which we find it - a generalist carnivore for example. Feeding on hare, birds, small mammals (such as wood mouse, lemming at times)

32/n But if Arctic fox, then it's a cold adapted species, with its fur turning full white in winter to match in with the snow cover. It also hunted small mammals, birds etc. So at c.29k the glacier is starting to move down from Scotland to Northern Ireland, but not quite there.

33/n and at c.31k Ireland is still ice sheet free, but if Arctic fox, were conditions cold? We do intend to do pollen analysis on intact cave sediments (with stratigraphy), which will give us important information on plants occurrence, infer climate too. Still more work to do.

34/n Giant deer:
old date - (a) 32,060yrs; (b) 34,100yrs; (c) 32,200yrs
new date - (a) 40,600yrs; (b) 42,100yrs; (c) 45,100yrs

We can see giant deer got older in time and appears to disappear from Ireland much earlier than previously thought, around 40k. Giant deer inhabit open

35/n landscapes, with many grasses being its diet. The landscape might have had small copses of woodland, where female giant deer could wander, with calves hiding in the undergrowth after birth. Giant deer calf weighs c.40kg at birth! Males shed their antlers annually and regrow

36/n them every year. Being long legged deer species, they could run fast across the grass plains of Ireland some 40-45,000 years ago. Males fighting other males, clash of their antlers being heard all around. A time of large animals and grass plains.

37/n Brown bear:
old date - (a) 33,310yrs; (b) 37,870yrs; (c) 32,430yrs
new date - (a) 35,000yrs; (b) 46,200yrs; (c) 31,250yrs

Brown bear been around a long time in Ireland and with other dates from other studies, they occur in Ireland before the ice age (above), & after the

38/n ice age, into the Mesolithic and Neolithic archaeological periods of Ireland (into c.5,000yrs). Though we do say bear occurred up to the Bronze age times some 3,000 years ago, but this was one of Peter's 100 original dates and so must be re-dated to know exact date.

39/n On the #IrishCaveBones project we will be investigating the diet of brown bears here through time - did they eat fish? berries? scavenge animal bodies or other kills by predators? We know they used caves as dens and hibernate in and also give birth to cubs in... but we

40/n we don't know much if anything about their ecology and how they fit into the palaeo-ecosystems in Ireland through time. Being here a long time on our timeline, they would have had to adapt to changing climates and a ice age too. More to come with our research over next year.

41/n Woolly mammoth:
old date - (a) 20,360yrs; (b) 27,150yrs; (c) 34,100yrs
new date - (a) 21,820yrs; (b) 31,230yrs; (c) 22,860yrs

Interesting new dates for woolly mammoth .... before the ice sheet of the last Ice Age moved across (some) of Ireland... and then early back in

42/n once the ice sheet started to retreat and before Ireland became an island. Early coloniser post ice age.... they were grazers of many plants so our island had LOTS of grass for these to survive on. Or were these giants the last ones of a remnant population?

43/n as you are seeing now, I hope, though we have dates, we still need to do a lot more research to know about all these species' past ecologies and natural history and how they fit into palaeoecosystems. This is what we are currently working on until end 2024.

44/n But knowing the date, lets us continue our research in more meaningful ways.

Back to the range of animal species ...

45/n Spotted hyena:
old date - 24,000yrs
new date - 33,240yrs

A major jump back to before the last Ice Age for this hyena, with it scavenging and hunting reindeer, giant deer, brown bear. Found only in Castlepook cave so far.

46/n Reindeer:
old date - (a) 12,480yrs; (b) 38,650yrs; (c) 35,200yrs; (d) 26,090yrs
new date - (a) 20,220yrs; (b) 41,700yrs; (c) 40,600yrs; (d) 31,000yrs

Reindeer are shifting backwards in time to older timeline, but very frequent in our cave bones. Certainly a native species.

47/n Horse:
old date - 27,630yrs
new date - 28,510yrs

We had lovely small wild horse (much like wild horses in Eastern Europe today) before the Ice Age and the ice sheet covered much of Ireland. We then need to jump forward to Killuragh cave horse at 3,020yrs Middle Bronze age.

48/n Arctic lemming:
A rodent that we don't think of living in Ireland in the past, but adapted to cold tundra conditions, still living in the Arctic circle today.

old date - 20,300yrs
new date - 28,860yrs

49/n and finally, our good friend the Grey Wolf:

old date - 23,470yrs
new date - 19,680yrs

A early (re)coloniser to Ireland after the ice sheet is in retreat, appearing in Castlepook cave. The wolf is interesting in terms of its prevalence in the Irish record - actual bones.

50/n We also have the grey wolf dated to the c.11,000 years ago in both Plunket cave (Sligo) and Ballynamintra cave (Waterford). But in general there is a lack of actual bones from this animal in the past 50,000 years (BUT we haven't dated too many either), and archaeological

51/n records. We do have Neolithic and Bronze age dogs from Killuragh cave, well we assume they are dogs, we will be working on their ancient DNA to determine what they are exactly. Whether these are dogs or wolves we will know soon. But what about all the folklore associated

52/n with wolves in Ireland? What if they were feral dogs instead? There is a lack of wolf bones identified in archaeological assemblages here, or were they misidentified as dogs? Cross-over to another project of mine #VikingDublinDogs @VikingDublinDog we are examinging dog bones

53/n and any 'wolf' bones found between c.700-1400AD, with some outliers older sites too. We will be extracting and comparing ancient DNA sequences, stable isotopes (diet and origins), bone measurements (sizes, population comparisons), and radiocarbon dating the bones too from

selected sites in Ireland and England. This is a grassroots project. But if there are wolves hidden amongst the dogs, or cross-breeds, we will find them. What if wolves were reintroduced by the Normans for hunting? When did wolves die out in Ireland for real? We are running a

55/n Kickstarter end of May into June to raise costs to cover radiocarbon dating. As the costs for the other analysis are covered by the respective labs involved. website for info: vikingdublindogs.ie Wolves won't remain hidden from us, no matter the clothing!

56/n Slight tangent, but important to mention the dog/wolf project as it ties into the #IrishCaveBones project too. So, we see from the new dates, that animals mainly jumped back to older times and in general there was a change in set of animals from about the 40kyr mark.

57/n From the late 30,000 years we see the origins of Irish animals that inhabited our island (back through time, our island was part of a larger land mass covering north into Scotland, and then later down SE to SW England and NW France, now covered in sea), some of these were

58/n present before the large glacier (British-Irish Ice Sheet) that formed during the last Ice Age, extended down into Ireland. As we see from Henry Patton et al. (2017) modelling, at c.34kyr, the ice is forming in Scotland, but there's a landbridge in north Ireland.

59/n As we continue to look at Patton's 2017 modelling, at c.27kyrs, the ice sheet has extended over much of Ireland, leaving parts of the south and southeast free of ice largely, and there's a landbridge connecting to SW England and NW France. Animals would have been using this.

60/n And at 17kyr, Patton's 2017 model show the ice sheet retreating, but Ireland is still attached to SW/NW England/France...again animals would have been using this area.

61/n But then Ireland becomes an island afterwards and by c.15kyrs it's separated from England/France- leaving any animals that can't swim long distances, fly or float stuck in Ireland. These animals are considered native, if got to Ireland without interference, under own steam.

62/n If you're still with me, thanks for reading. I know this is a long thread, but there is so much info and this is skimming the surface, and we have more questions than answers at the moment, but we are working on these and more!

63/n Regarding the Kilgreany cave lynx bones -from immature lynx - partial mandible & partial femur - these were dated as part of Peter's 100 dates in mid 1990s &must be redated to find out exactly their date in our timeline, before we can really get into a reintroduction chat.

64/n So how to decide on what's native and what's not? Species that arrived and survived/breeding in Ireland under their own steam without human interference or help, these are considered native species. Is time important, is there when they were here of use? Some say no...

65/n some say yes if they were here, then why not reintroduce them? We need to engage with ecologists and palaeoecologists (like ourselves) to ascertain what sort of palaeoecosystem the species survived and thrived in, and then if suitable habitats availabe today? or will species

66/n survive and thrive in modern times? or will they, through their (re)introduction, 'fix' the habitats? What will be the source populations that the animals are sourced from? How many to make a thriving surviving population? There are many questions that must be considered but

67/n first we need to investigate and determine how they survived and thrived in the past, when they were numerous across our island. Some animals in Ireland could be considered as naturalised species - introduced outside its native range, establishes self-sustaining populations.

68/n But how do these naturalised species effect the 'native' species? And if there is suitable habitat and not doing damage, then do we accept them as part of our fauna? For example, red squirrels were introduced from their native Britain to Ireland in 1700-1800s+, but we call

69/n them native species here. But they aren't, but we accept them as such. Why? They don't do damage to the habitats they are in .... but at no point are they in our archaeological/Quaternary records. So it's okay? They are a naturalised species.

70/n Perhaps we should get away from calling animals 'native'.... as it's a time associated limitation. Would not being part of a functional ecosystem, past or present, not be more important? Or do we have a before Ireland became a island and post-island formation designation?

71/n I think by learning from our past and through palaeo-foodwebs and palaeo-ecosystems, we can learn much how species fit like jenga puzzle in our landscape and when remove one species, what happens? Fortunately, we can see this in the past and see effects, which will inform

72/n our current ecosystem management & future too. We have only begun to scratch the surface with our research and work into Ireland's past and its animals, and it can give us so many answers. Food for thought tonight, no answer is right/wrong, but it leads to great discussions.

73/73 I'll leave ye to think and chat.... but our work is not yet done and we will continue to learn about our past. Tomorrow, Day 5, We will take a look at some human-animal relationships in Ireland during the past with a focus on one in particular. Good night for now. Ruth